Toro Service Manual

TORO/LAWN-BOY WALK BEHIND POWER MOWER DRIVE SYSTEMS MANUALTable of Contents – Page 1 of 2 TRANSMISSION USAGE WORM DRIVE TRANSMISSION SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION SINGLE SPEED BEVEL GEAR TRANSMISSION THREE SPEED TRANSMISSION WORM DRIVE TRANSMISSION GENERAL INTERNALLY CLUTCHED DESCRIPTION LUBRICATION THE SHIFTING PROCESS REMOVAL AND INSTALLATION (FRONT WHEEL DRIVE APPLICATIONS) DISASSEMBLY ASSEMBLY CONTROLS ADJUSTMENT CONSTANT MESH DESCRIPTION REMOVAL AND INSTALLATION CONTROLS SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION GEAR CASE ASSEMBLY INTRODUCTION LUBRICATION DISASSEMBLY ASSEMBLY CABLE ADJUSTMENT SINGLE SPEED BEVEL GEAR TRANSMISSION EXPLODED VIEW - SINGLE SPEED BEVEL GEAR TRANSMISSION GENERAL INFORMATION FRONT AXLE AND TRANSMISSION ASSEMBLY FRONT WHEEL DRIVE MODELS TRANSMISSION DISASSEMBLY TRANSMISSION DISASSEMBLY TRANSMISSION ASSEMBLY ASSEMBLY TIPS BELT SERVICE - FRONT WHEEL DRIVE MODELS REAR WHEEL DRIVE MODELS TRANSMISSION REMOVAL AND BELT REPLACEMENT REAR AXLE DISASSEMBLY TRANSMISSION DISASSEMBLY TRANSMISSION ASSEMBLY AXLE ASSEMBLY TIPS WHEEL PINION SERVICE 22" STEEL DECK TRACTION ADJUSTMENTS BAIL CONTROL PERSONAL PACE TORO/LAWN-BOY WALK BEHIND POWER MOWER DRIVE SYSTEMS MANUAL Table of Contents – Page 2 of 2 THREE SPEED TRANSMISSION GEARCASE ASSEMBLY OPERATION REMOVAL - TORO VACU POWER/LAWN-BOY MEDALLION MODELS REMOVAL - RECYCLER/REAR BAGGER CHASSIS ALTERNATE METHOD DISASSEMBLY TRANSMISSION - ASSEMBLY OUTPUT SHAFT ASSEMBLY INPUT SHAFT ASSEMBLY INTERMEDIATE SHAFT ASSEMBLY INSTALLATION SPECIAL ASSEMBLY NOTES FOR TORO VACU POWER/LAWN-BOY MEDALLION TROUBLESHOOTING TIPS - 3 SPEED TRANSMISSION HARD SHIFTING SLIPPING GEARS CABLE ADJUSTMENT WHEEL PINION CLUTCH GEARCASE AND WHEEL ASSEMBLY REAR HEIGHT-OF-CUT AND WHEEL PINION CLUTCH - DISASSEMBLY REAR HEIGHT-OF-CUT AND WHEEL PINION CLUTCH - ASSEMBLY BLADE BRAKE CLUTCH SYSTEMS (BBC) CLUTCH OPERATION CONTROL BOX OPERATION HANDLE CONTROLS CONTROL BOX DISASSEMBLY CONTROL BOX ASSEMBLY TORO BBC SERVICE GUIDE BLADE BRAKE CLUTCH ASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLIION) TORO VACU POWER LAWN-BOY / MEDALLION BBC BELLCRANK SYSTEM DISASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION) BELLCRANK SYSTEM ASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION) UNDER DECK COMPONENTS DISASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION) UNDER DECK COMPONENTS ASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION) BBC CABLE REMOVAL (TORO VACU POWER / LAWN-BOY MEDALLION) BBC CABLE INSTALLATION (TORO VACU POWER / LAWN-BOY MEDALLION) BBC CABLE ADJUSTMENT (TORO VACU POWER / LAWN-BOY MEDALLION MODELS) ENGINE AND BLADE ASSEMBLY (TORO RECYCLER / REAR BAGGER) TORO RECYCLER / REAR BAGGER BBC IDLER ARM SYSTEM DISASSEMBLY (RECYCLER / REAR BAGGER) IDLER ARM SYSTEM ASSEMBLY (RECYCLER / REAR BAGGER) BBC CABLE REMOVAL (RECYCLER / REAR BAGGER) BBC CABLE INSTALLATION (RECYCLER / REAR BAGGER) BBC CABLE ADJUSTMENT (RECYCLER / REAR BAGGER) WALK BEHIND POWER MOWER DRIVE SYSTEMS SERVICE MANUAL please contact us at the following address: The Toro Company Consumer Service Department 8111 Lyndale Avenue South Bloomington. The Toro Company has made every effort to make the information in this manual complete and correct. MN 55420-1196 The Toro Company reserves the right to change product specifications or this manual without notice. We hope you find this manual a valuable addition to your service shop.ABOUT THIS MANUAL This service manual was written expressly for Toro servicing dealers. If you have questions or comments regarding this manual. This manual was written with the assumption that the reader has basic mechanical knowledge and skills. and may be specified for use on products built after 2002 that are similar in design. Copyright© All Rights Reserved ©2001 The Toro Company . This book contains material covering the Toro and Lawn-Boy Walk Behind Mower Drive Systems models from 1990 to 2002. . . . . . . . . . . . . . . . . . .4 Assembly . . . . . . . . . . . . . . . . . .1 Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . .2 . . . . . . . . . . . . . . . . . . . . .2 Disassembly . . . . . .1 . . . .1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . .2 The Shifting Process . . . . .9 Removal And Installation . . . . . . . . . . . . . . . . . . . . . .2 Lubrication . . . .1 Description . . . . . . . . . . . . . . . . . . . . . . . . . Three Speed Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . .6 Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 . . . . . . . . . .4 Walk Behind Power Mower Drive Systems Manual i . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 . . . . . . . . . v v v v WORM DRIVE TRANSMISSION General . . . . . . . . . .2 . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . .8 Constant Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Cable Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Adjustment . . . . . . . . . . . . . . . . . . . .1 Internally Clutched . . . . . . . . . . . . . . . . . .9 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Removal and Installation (front wheel drive applications) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 . . . . . . . . . . . .1 . . . .1 . . . . . . . . . . . . . . . .11 SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION Gear Case Assembly . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Controls . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . .3 Disassembly . . Single Speed Bevel Gear Transmission . . . . . . Single Speed Spur/Bevel Gear Transmission . . .2 Assembly . . . . . . . . .TABLE OF CONTENTS TRANSMISSION USAGE Worm Drive Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 . . . . . . . . . . . . . . . . . .2 . . . . . . . . . . . . . . . Transmission Disassembly . . . . . . . . . . . . . . . . . . . . .13 Transmission Assembly . . . . .Front Wheel Drive Models . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Transmission Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . Belt Service . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 ii Walk Behind Power Mower Drive Systems Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Rear Axle Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . .1 General Information . . . . . . . . . . . . . . . . . . . . . . . . 3-4 3-4 3-5 3-6 3-6 3-7 Rear Wheel Drive Models . . . . . . . . . . . . . .8 Transmission Removal and Belt Replacement . . . . Transmission Disassembly . . . . . 3 . . . . . . . .2 Front Axle And Transmission Assembly . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Single Speed Bevel Gear Transmission . . . . . . . . . . . . . . .13 Wheel Pinion Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Personal Pace . .13 Axle Assembly Tips . . 3 . . . . . . . . . . . . . . . .14 22” Steel Deck Traction Adjustments . . . . . . . . . . . . . . . . . . . . . . .15 Bail Control . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmission Assembly . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Assembly Tips . . . . . . . . . . . . . . . 3 . . . . . . . . .TABLE OF CONTENTS SINGLE SPEED BEVEL GEAR TRANSMISSION Exploded View . . . . . . . . . . . . . 3 . .3 Front Wheel Drive Models . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . .1 Operation .Disassembly . . . . . . . . .4 .10 WHEEL PINION CLUTCH Gearcase And Wheel Assembly . . . . . . . . .5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . . . . . . . .4 Transmission . . . . . . . . . . . . . . .1 Rear Height-Of-Cut And Wheel Pinion Clutch . .5 Output Shaft Assembly . . . . . . . . . . . . .5 . .5 . . . . . . . . . . . . . .8 Special Assembly Notes For Toro Vacu Power/Lawn-Boy Medallion .4 . . . . . . . . . . .4 . . . . . . . . . . .Toro Vacu Power/Lawn-Boy Medallion Models . . . . . . . . . . . . . . .Assembly . . . . . . . . . . . . . . . .4 . . . . . . . . .4 . . . . . . . . . . . . .9 Cable Adjustment . . . . . . . . . .8 Troubleshooting Tips . . . . . . . . . .2 Removal . . . .4 . . . . . . . . . . . . . . . . . . .4 Walk Behind Power Mower Drive Systems Manual iii . . . . . .Assembly . . . . . . . . . .3 Speed Transmission . . . . . . . . . . . . . . . . . . . . . . . .Recycler/Rear Bagger Chassis . . .9 Slipping Gears . . .4 . . . . . . . . . . . . .4 . . . . . . . . . . . . . . . . . . . .9 Hard Shifting . . . . . . . . . . . . .7 Installation . . . . . . . . . . . . . . . .4 Disassembly . . . . . . . . . .4 . . . . . . . . .6 Intermediate Shaft Assembly .3 Removal . . .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Input Shaft Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Rear Height-Of-Cut and Wheel Pinion Clutch . . . . . . . . . . . . . . . . . . . .4 Alternate Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TABLE OF CONTENTS THREE SPEED TRANSMISSION Gearcase Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . .4 . . . . . . . . . . . . . . . . . Handle Controls . . . . . BBC Cable Adjustment (Recycler / Rear Bagger) . . . . . . . . . . . .22 6 . . . . . 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 BBC Cable Adjustment (Toro Vacu Power / Lawn-Boy Medallion Models) . . . . . . . . . . . . 6 . .26 iv Walk Behind Power Mower Drive Systems Manual .20 6 . . . . . . . . . . . . . . . .20 6 . . . . . . . .17 Engine And Blade Assembly (Toro Recycler / Rear Bagger). . . . . . . . . . . . . . . 6 . . . . . . . .8 Toro Vacu Power Lawn-Boy / Medallion BBC . . . . .24 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 BBC Cable Installation (Toro Vacu Power / Lawn-Boy Medallion) . . . .7 Blade Brake Clutch Assembly (Toro Vacu Power / Lawn-Boy Medalliion) . . . . . . . . . . . . . . . . . . . . . . . 6 . . . . . . . . Control Box Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Idler Arm System Assembly (Recycler / Rear Bagger) . . . .9 Bellcrank System Disassembly (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Bellcrank System Assembly (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . . . . . . . . . . BBC Cable Installation (Recycler / Rear Bagger) . . . . . .10 Under Deck Components Disassembly (Toro Vacu Power / Lawn-Boy Medallion) . 6-1 6-1 6-2 6-4 6-5 Toro BBC Service Guide . 6 . . . . . . . . . . . . . . . . . . . . . . . 6 . . . .11 Under Deck Components Assembly (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . . . . . . . . . . . Control Box Assembly . . . . . . . . . . . . . . .25 6 . . . . . . . . . . . . . . . . . BBC Cable Removal (Recycler / Rear Bagger) . Control Box Operation . . . . . . . . . . . . . . . . . . . . 6 . . . . . . 6 . . . . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . . Idler Arm System Disassembly (Recycler / Rear Bagger) . . . . . . . . . . . .14 BBC Cable Removal (Toro Vacu Power / Lawn-Boy Medallion) . . . 6 . . . . . . . . . . .19 Toro Recycler / Rear Bagger BBC . . . . . . . . . . 6 . . . . . .TABLE OF CONTENTS BLADE BRAKE CLUTCH SYSTEMS (BBC) Clutch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TABLE OF CONTENTS TRANSMISSION USAGE Worm Drive Transmission Toro Models 16212 16212B 16212W 16212WG 16401 16402 16403 16404 16411 16775 16776 16785 16793 20905 20905B 20906B 20911B 20915 20916B 20920 20920B 20921B 20925 20925B 20926B 20927B Single Speed Spur/Bevel Gear Transmission Toro Models 20011 20020 20021 20028 20442 20444 20711 10301 10302 10304 10305 10307 10309 10310 10311 10312 10313 10314 10316 10317 10318 Lawn-Boy Models 10319 10320 10321 10323 10324 10324C 10327 10328 10329 10330 10331 10332 10334 10335 10342 10343 10344 10345 10360 10360C 10361 10362 10363 10550 10551 10552 10910 10910B 10915 10915B 10926 10927 10929 Single Speed Bevel Gear Transmission Toro Models 20012 20013 20014 20016 20017 20018 Three Speed Transmission Toro Models 20044 20106 20210 20211 20214 20216 20218 20219 20320 20321 20322 20324 20325 20327B 20328B 20436 20436WF 20437 20438 20438WF 20439 20439WF 20462 20463 20464 20465 20466 20470 20472 20473 20474 20475 20476 20478 20479 20480 20481 20482 20483 20486 20487 20488 20489 20490 20494 20495 20622 20666 20667 20668 20677 20680 20692 20761B 20763B 20764B 20764BC 20766B 20766BC 20767B 20768B 20776 20777 20778 20786 20787 22035 22036 22037B 22037BC 22038 22038B 22040 22042 22043 22044BC 22045 22045B 22141 22142 22150 22151 22153BC 22154 22154B 22157 26620B 26620BF 26620BG 26621 26621B 26622 26623 26624 26625B 26625BG 26626 26630B 26630BC 26630BG 26631B 26631BC 26632 26632B 26633 26633B 26635B 226635BC 26635BG 26636 26636B 26637 26638 26639 26640B 26640BC 26643 26643B 26680 26680WG 26682 26683 27500 27501 27502 Lawn-Boy Models 10515 10516 10517 10518 10519 10520 10521 10522 10523 10524 10525 10527 10528 10533 10545 10546 10547 10548 10590 10591 10750 10760 10761B 10762B 10928 11001 11001B 11003 Walk Behind Power Mower Drive Systems Manual v . THIS PAGE INTENTIONALLY LEFT BLANK vi Walk Behind Power Mower Drive Systems Manual . The worm shaft (input shaft) is driven by a belt from the engine crankshaft. The first is a clutch type and is used on 21” front wheel drive mowers. The worm is in constant mesh with the helical gear. pivots the transmission forward to maintain tension on the belt. The clutching action is provided by a sliding clutch jaw.WORM DRIVE TRANSMISSION GENERAL There are two versions of the worm drive transmission. power is transferred from the clutch jaw to the sleeve inside the clutch jaw. A B E C D F G Figure 1 (A) (B) (C) (D) Belt Spring Helical Gear Clutch Jaw (E) Shift Fork (F) Sleeve (G) Input Shaft (worm shaft) Walk Behind Power Mower Drive Systems Manual 1-1 . The second version is constant mesh and is used on International 48cm rear wheel drive mowers. The sleeve is pinned to the axle. When the clutch jaw engages the helical gear. The axle then begins to rotate. INTERNALLY CLUTCHED Description: This is a worm and helical gear transmission. A shift fork moves the clutch jaw to engage and disengage the transmission. A spring which hooks into the tab on the front of the transmission (where the roll pin is) and to the mower housing. then to the rear. This moves the shift pin. oil will leak out only to the bottom of the seal on the axle. the shift fork. This spring pushes the shift fork and clutch jaw towards the engaged position (Figure 2). This type of transmission will last less than 30 minutes with no lubrication. Unless the case is cracked. B Figure 2 (A) Shift Rod (B) Shift Fork 3428-0150 1-2 Walk Behind Power Mower Drive Systems Manual . The transmission has a fill/check plug in the front. If a transmission lasts even a few weeks in consumer use. tension on the shift arm is released. If gear failure occurs. A variable weight such as 85w 90 is acceptable as long as the range includes 90 weight. NOTE: Dirt packed in the latch plate can prevent disengagement. (A) (B) (C) (D) Roll Pin Latch Plate Dust Filter Dust Cover Figure 3 (E) Shift Arm (F) Screw (G) Shift Rod The shift rod has a roll pin protruding through the top of the transmission. oil can not leak out. With the transmission level. the resulting friction can cook the oil down to a smear in the bottom of the case. fill until level with the hole. The spring on the shift rod applies pressure to the rod. The Shifting Process The upper end of the clutch fork slides over a groove in a spring loaded rod. The shift arm on top of the transmission holds all these parts in place (Figure 3). The second part of the requirement is an EP rating of GL 5 or higher.WORM DRIVE TRANSMISSION Lubrication This transmission requires 90 wt. NOTE: This is equal to about the center of the axle. Even if a seal fails. When the shift cable is engaged. gear oil. Above the latch plate is a dust filter and a dust cover. This does not indicate a lack of lubrication. the pin moves to the left side of the mower. fork. This pin goes through a latch plate with an L shaped slot in it. it had lubrication to start. . The slot guides the pin in its travel from engagement to disengagement. and clutch jaw to engage the transmission. and the clutch jaw to the disengage position. G A B C D E F 3428-0165 A When the shift arm is pulled to the rear by the shift cable. The dust filter and dust cover help prevent this failure. 5. (This removes the tension from the pivot arms so the roll pin can be removed (Figure 6). Pivot (both) front spring arms forward until they point straight down.WORM DRIVE TRANSMISSION Removal and Installation (front wheel drive applications) 1. A B C Figure 6 Figure 4 (A) Cable Clamp (B) Shift Cable 2. . Place a block of wood under the wheel pinion for support and drive the roll pin out of the axle (Figure 7). 3. Repeat the process on the other side. Slip the belt off the transmission pulley (Figure 4). Remove the belt cover and unhook the spring on the front of the transmission. A Figure 7 (A) Wood Block 3428-0135 Figure 5 3428-0129 Walk Behind Power Mower Drive Systems Manual 1-3 . (C) Spring 3428-0127 3428-0131 6. Raise the front of the mower off the bench and support it with blocks. . 4. Remove both front wheels and wheel covers (Figure 5). Disconnect the shift cable. Cut and discard the push-on retainer on top of the transmission pulley. NOTE: Support the wheel pinions with the wood block while driving the roll pins in. Fill the transmission with oil after it is installed in the mower (Figure 9). (These pins align the top and bottom parts of the case (Figure 10). C Figure 9 (A) Tab (B) Plug B A 3428-0166 (C) Fill/Check 1-4 Walk Behind Power Mower Drive Systems Manual . 2. This is not a sealed case. Figure 8 8. 3. Remove the belt and pulley. pivot. . The wheel pinion. 1. Reverse the procedure to install. Repeat the process on the other side. 9. Figure 10 3428-0146 Remove the 4 self-tapping screws that connect the top and bottom cases. thrust washer. Disassembly Note the front of the transmission is identified by the oil fill/check screw and the flat tab which is part of the lower case. NOTE: If you turn this transmission on its side or upside down. 3428-0137 Remove the transmission from the chassis. Drive the roll pins out of the flanges in the front and rear of the case. and spring arm will now slide off the end of the axle (Figure 8). This will prevent the axle from being bent. oil may leak out of the top.WORM DRIVE TRANSMISSION 7. Clean the oil residue and any metal shavings from the case. (C) Sleeve (D) Clutch Jaw Clean the old gasket material from the mating surfaces of the case and cover. The shift fork may come with the cover or may fall into the bottom of the case (Figure 11). (A) Helical Gear (B) Thrust Washer 9. 3428-0151 If the axle bearings are to be re-used. A B C D Figure 13 Figure 11 5. To remove the axle. 10. slide the clutch jaw to the side and drive the roll pin out of the sleeve and axle (Figure 12). 6. clutch jaw. Remove the transmission cover. A hook or small screwdriver can be used to pry the seals out of the case. and thrust washer (Figure 13). Walk Behind Power Mower Drive Systems Manual 1-5 . 11. helical gear. Remove the sleeve. clean the end of the axle before drawing it out of the case. 12. 3428-0148 3428-0153 Push the worm shaft out of the cover. 8. This may require a little pressure. Figure 12 7.WORM DRIVE TRANSMISSION 4. An arbor press or large vise will be needed when removing and replacing the bushings. Figure 16 (A) Tool P/N 27-0460 2. Refer to Figure 12. and the sleeve and clutch jaw. The bushings should be flush with the inside of the case (Figure 16). NOTE: Some replacement axles have more than one hole that can be used to pin the sleeve to the axle. Wipe the inner diameter of the bushings with a clean cloth. NOTE: The bushings are two different lengths. Then drive a roll pin through the sleeve and axle. insert the short end of the axle from left to right. to press in new axle bushings. Remove the roll pin and pull shifter rod out of the cover. 3428-0158 G A B C D E F Figure 15 (A) (B) (C) (D) Roll Pin Latch Plate Dust Filter Dust Cover (E) Shift Arm (F) Screw (G) Shift Rod 3428-0165 Clean the rust and dirt from the both ends of the axle. Use bushing installation tool. Worm and helical gears are sold as a set. Assembly 1. This tool helps keep the bushing straight and keeps the inner diameter of the bushing correctly sized. Lightly oil the axle and insert it into the gearcase. Then push the axle through the other side of the case. Replacing only one gear will result in rapid failure (Figure 14). 1-6 Walk Behind Power Mower Drive Systems Manual . When facing the front of the gearbox. Refer to the original axle to identify the correct hole to use. Even after a short run time. P/N 27-0460. they will develop a wear pattern. Install the thrust washer. Clean the cover. press it out at this time. and wear plate (Figure 15). If the ball bearing is to be replaced. A A B Figure 14 (A) Worm Shaft 3428-0157 (B) Helical Gear 14. dust cover. 15.WORM DRIVE TRANSMISSION 13. Remove the screw from the shift arm and remove the shift arm. 3. The side of the case with the thicker boss uses a longer bushing to support the axle. helical gear. slide new seals down each side of the axle. Using a seal protector. The top of this transmission is not sealed. Install the cover on the bottom case and start the 4 self-tapping screws. Install the seal with the lip facing the transmission. Then secure the 4 self-tapping screws.WORM DRIVE TRANSMISSION 4. Do not fully tighten them. Press the bearing in until it is fully seated in the case (Figure 18). 6. A B Figure 17 (A) Cellophane 5. It will leak if tipped on its side (Figure 19). Install the front and rear roll pins to align the cover and case. If a seal protector is not available. Fill the transmission with gear oil AFTER it is installed in the mower. This bearing only has one seal. use tool P/N 27-0490 to press it in place. 8. (B) Seal 3428-0170 A B Figure 19 (A) Fill/Check (B) Plug 3428-0166 If the bearing in the cover is being replaced. wrap a piece of cellophane around the axle (Figure 17). A Figure 18 (A) Tool 27-0490 3428-0159 Walk Behind Power Mower Drive Systems Manual 1-7 . Use a new gasket. The outer edge of the seal should be flush with the outside of the case. 7. Install the bearing such that the seal is visible from the top of the cover and the open side faces the gears. pull the control to the rear (disengage). To adjust. the other controls the transmission. Go to the cable clamp/adjustment. Since the spring and pin on top of the transmission pushes the shift fork towards the engaged position. Loosen the clamp. pull the cable to the rear until the shift lever is as far back as it will go. Hold it there and tighten the clamp (Figure 20). One cable operates the engine kill switch and flywheel brake. A Figure 20 (A) Cable Clamp 3428-0127 1-8 Walk Behind Power Mower Drive Systems Manual . the cable pulls the shift arm to the rear to disengage the transmission. Adjustment The transmission cable is a standard lever type. The adjustment point is on the mower housing just to the rear of the transmission.WORM DRIVE TRANSMISSION Controls There are two control cables used with this system. However. Engagement and disengagement is accomplished by pivoting the transmission to tighten or loosen the belt.WORM DRIVE TRANSMISSION CONSTANT MESH Description: This transmission is very similar to the “INTERNALLY CLUTCHED” on page 1 . as is the lubrication requirement. gear oil rated GL-5 or higher. 90 wt. the helical gear is different as there is no internal clutching (Figure 21).1. Figure 21 (1) Jam Nut (2) Lock Washer (3) Half Pulley (4) V Belt (5) Pulley Spacer (6) Gearbox Cover (7) Shaft & Worm (8) Ball Bearing (9) Gearbox Gasket (10) Check Plug (11) Gasket Check Plug (12) Bushing (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) Oil Seal Output Shaft Traction Bracket Thread Forming Screw Gearbox Case Thrust Washer Roll Pin Helical Gear Thrust Washer Bushing Roll Pin The constant mesh type transmission is used in a 48cm rear wheel drive application. Internal repair procedures are the same. Walk Behind Power Mower Drive Systems Manual 1-9 . 10 Walk Behind Power Mower Drive Systems Manual . 1 2 2 2 2 2 4 2 2 2 4 2 1 Description L. 5 & 14) Locknut Thread Forming Screw Trigger Return Spring H.WORM DRIVE TRANSMISSION Removal And Installation Figure 22 Ref. Ref. 4. (Incl. #2. Saddle Thread Forming Screw Push Nut Needle Bearing Friction Washer Keyed Thrust Washer Retaining Ring Ref. 4. 1 2 2 2 2 1 2 1 2 1 2 1 2 2 4 4 Description Rear Pivot Assembly R. 18 19 20 21 22 23 24 25 26 27 28 34 35 Qty. #24) Wheel Bolt Wheel Bushing Wheel Spacer Clutch Washer Rear Suspension Plate Thread Forming Screw Roll Pin Gearbox Assembly 1 . (Incl.H.O. 5 & 14) Grease Fitting Washer Sleeve Bushing Grease Seal Rear Pivot Assembly L. 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 Qty. Ref. Rocking Key Pinion Gear Compression Spring Wheel Cover Tire & Gear Assy Wheel (Incl.H. No.C. No.H. #2. Ref. Remove the belt. repeat steps 2 . Remove both rear wheels. Each bracket has 2 screws. keys. Once they are removed. The cable is adjusted correctly when resistance is felt when the control bar is approximately 1” (25mm) from the upper handle (Figure 24). the transmission will drop out. 2. and pivot arms on both sides ("Wheel Pinion Clutch" on page 5 . The top of the transmission is not sealed. springs. or 1/2 turn counterclockwise to loosen the belt. Figure 24 4. Walk Behind Power Mower Drive Systems Manual 1 . Controls Adjusting Wheel Traction Drive 1. so it may leak if filled and tipped. slowly squeeze the control bar towards the handle. 2. reverse the above process. gears.3 until properly adjusted. Stop the engine. Fill the transmission level with the fill plug after it is installed in the chassis. 2) Cable 3. To install. There is a suspension bracket on each side that secures the transmission and pivot arms to the chassis. Rotate the adjustment knob under the lower lefthand side of the control panel 1/2 turn clockwise to tighten the belt.WORM DRIVE TRANSMISSION To remove the transmission from the mower proceed as follows: 1. Remove the retaining rings. If loss of traction or improper engagement still occurs after adjustment. To check the adjustment. Figure 23 1) Knob 3.11 . 4. clutches. Hold the control cable while rotating the knob to prevent the cable from turning (Figure 23).1). 12 Walk Behind Power Mower Drive Systems Manual .THIS PAGE INTENTIONALLY LEFT BLANK 1 . 37t Pinion Gear Bevel Gear Output Shaft Walk Behind Power Mower Drive Systems Manual 2-1 . 1 1 4 1 1 2 1 2 2 2 2 1 2 1 1 1 1 1 1 Description Gear Case Casting Gear Case Cover HWH Screw Retaining Ring Flat Washer Groove Pin Lock Nut NI Washer Thrust Washer Bushing Output Bushing Intermediate Shaft Pulley Half Ball Bearing Pulley Spacer Bevel Gear 15t Spur.SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION GEAR CASE ASSEMBLY Figure 25 Ref. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Qty. Some models have the axle shaft retained by an end cap. causing an increased tendency for belt jumping. All use a bevel pinion input gear which mates with a combination bevel/spur gear. This often results in damage to the belt or slightly bending the belt guide. Figure 27 3428-0078 The transmission can be moved to the right until the short end of the axle clears the housing and the transmission can be removed (Figure 28).9.5 . There are minor variations.1cc .1 for disassembly and repair procedures for the wheel clutches. Do not try to force the belt without loosening the belt guide. such as different shafts on the bevel pinion gear to accommodate belt alignment on different chasses.SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION Introduction This basic transmission has been in use for several years. Once the wheel clutches are removed.3 fluid ounces (7. slide the pivot and spring arms off the axle (Figure 26). removing these 2 screws makes transmission removal easier (Figure 29). Disassembly Refer to "Wheel Pinion Clutch" on page 5 . Loosen or remove the belt guide so the belt can be slid off the transmission pulley (Figure 27). 2 grease. On some models. Figure 28 3428-0074 Figure 26 3428-0030 2-2 Walk Behind Power Mower Drive Systems Manual .0cc) of lithium based No. which drives a final spur gear. Lubrication Proper lubrication for this transmission is 2. replace the mate for the damaged gear.SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION A A Figure 29 (A) End Cap The nut on the pulley can be removed now. Clean the gears in solvent and inspect carefully. Remove the axle and intermediate shaft with the gears. The spacer under the pulley varies with the chassis and the length of the shaft on the pinion (Figure 30). Also. 3428-0121 Figure 31 (A) Washers Figure 32 3428-0018 Figure 30 3428-0008 Before removing the parts from the case. Replace as necessary. The bearing in the cover should be sealed on both sides. Inspect the bearing and its seals for damage (Figure 32). note the quantity and location of the thrust washers (Figure 31). Make sure bearing is fully seated. Any damaged gear must be replaced. Walk Behind Power Mower Drive Systems Manual 2-3 . The bearing is pressed into the cover. The exception for this is if the transmission has VERY little running time before failure. Remove the selftapping screws holding the cover on the transmission. When gears run together. they develop a wear pattern that will result in premature failure if only one gear is replaced. Figure 35 3428-0022 Figure 33 Assembly 3428-0016 Insert the transmission back into the chassis. The internal gears will help hold the pinion while the nut is tightened (Figure 35). Add grease and install the cover. The other pin aligns the axle and transmission case. Finally. Assemble with the correct number of thrust washers. it is wise to apply a light coat of engine oil to the running surface (Figure 34).SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION The axle has two roll pins through it. Cable Adjustment There are several variations of control systems used with this single speed transmission. One connects the single spur gear to the axle (Figure 33). Figure 34 3428-0019 2-4 Walk Behind Power Mower Drive Systems Manual . Prior to installation of oil impregnated bushings. install the spacer and pulley on the input shaft. Refer to the section on the wheel pinion clutch for assembly instructions. Refer to the parts manual if there is any doubt at all. It is not possible to locate the shafts and bearings in the wrong location. due to differences in sizes. In either case. The same system on a Lawn-Boy is called the Easy Stride. Draw the cable conduit down to remove the slack. when the bail is squeezed completely. The bail type was used on both Toro and LawnBoy models. Remove the belt cover to push the front of the transmission down and hold. The other system is the Toro Personal Pace (Figure 38). The adjustment point for this system is where the cable is clamped to the upper handle.SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION 1. loosen the cable clamp. the mower propels at full speed and when the bail is lowered about 1” (25mm). Hold the cable and tighten the clamp (Figure 39). A A Figure 36 (A) Clamp 3428-0049 Figure 38 (A) Clamp 3428-0047 Figure 37 Figure 39 1) Knob 2) Cable 0185-15 Walk Behind Power Mower Drive Systems Manual 2-5 . and some had an adjusting knob (Figure 37) in the cable. Some used a cable clamp (Figure 36). 3. To adjust this type of system. the wheels stop driving. THIS PAGE INTENTIONALLY LEFT BLANK 2-6 Walk Behind Power Mower Drive Systems Manual . SINGLE SPEED BEVEL GEAR TRANSMISSION A B K I G H F E J C D (A) (B) (C) (D) (E) (F) Pulley Spacer Bearing Pinion Bushing Roll Pin (G) (H) (I) (J) (K) Axle Bushing Thrust Washer Bevel Gear Housing Walk Behind Power Mower Drive Systems Manual 3-1 .SINGLE SPEED BEVEL GEAR TRANSMISSION EXPLODED VIEW . The pinion gear has ratchet teeth on the inside. When released. the wheel gear spins the pinion and it rolls over the key. The bevel gear is reversed when used in the front drive versus the rear drive. Clutching is done by rocking the transmission and tightening or loosening the drive belt (Figure 40). it will depress when the pinion tooth passes over it. Wheel clutches on all models are of a key/spring or ratcheting style. In both cases. the weight of the transmission causes it to rock towards the engine to disengage. As the key is supported by a spring. the gears are in constant mesh. When the axle begins to turn. the key engages one of the teeth and drives the pinion. Each drive pinion is independent from the other (Figure 41). It is used in both front wheel and rear wheel drive configurations. The cable will move the transmission to tighten the belt.SINGLE SPEED BEVEL GEAR TRANSMISSION GENERAL INFORMATION This transmission was first used on 22” steel deck models for 2002. a ratcheting sound will be heard. When pulling a mower with this type of drive backwards. Figure 40 mvc-485 3-2 Walk Behind Power Mower Drive Systems Manual . You will hear the sound of the gears turning if the engine is off. When the mower is pushed faster than the drive. the transmission output shaft will rotate. If the engine is not running. The key and spring are set in a keyway in the axle with the spring holding the key up. HOC Ball Bearing. HOC Retaining Ring Bearing Retainer. NI Front Belt Cover Walk Behind Power Mower Drive Systems Manual 3-3 . 13t Thrust Washer Stepped Washer Wheel Cover Front Pivot Arm Spring Arm Lever Knob. No. 2 2 1 1 2 1 2 1 1 2 1 1 1 Description Compression Spring Key Transmission ASM Shield Washer HWH Screw Pivot Bracket HWY Screw Spacer V-Belt Front Half Pulley Flat Washer Lock Nut. Unground Ref. 14 15 16 17 18 19 20 21 22 23 24 25 26 Qty. 2 2 2 4 2 6 2 2 2 2 2 2 2 2 Description Shoulder Bolt Wheel Gear ASM Bushing Klip Ring Pinion Gear. 1 2 2:1 3 4 5 6 7 8 9 10 11 12 13 Qty. Ref.SINGLE SPEED BEVEL GEAR TRANSMISSION FRONT AXLE AND TRANSMISSION ASSEMBLY Figure 41 Note: Front wheel drive version shown. No. Remove the wheel cover. transmission pulley halves. note there is a washer between the wheel and wheel cover. Figure 43 4. They are accessed from the bottom (Figure 42). Remove the nut. Grip the axle with locking pliers and remove the locknut on the transmission pulley (Figure 43). remove the klip ring and thrust washer. mvc-482 Figure 44 (A) Key 7. 3-4 Walk Behind Power Mower Drive Systems Manual . The axle assembly will now drop out of the chassis. 6. 3. mvc-472 Slip the belt out between the transmission pulley and belt guide. There are two screws that secure the belt cover to the housing. The pinion will now slide off the axle (Figure 44). Remove the belt guide. NOTE: The drive key and spring are under the pinion. Block the front of the mower up. To remove the wheel pinions. There is a notch in the pivot arm for clearance for a socket (Figure 45). washer. Remove both front wheels. A Figure 42 2. and spacer. Remove two bolts and nuts securing each pivot arm to the housing. mvc-475 After the wheel pinions are removed there is another thrust washer and klip ring that holds the pivot arm assembly together.SINGLE SPEED BEVEL GEAR TRANSMISSION FRONT WHEEL DRIVE MODELS Transmission Disassembly 1. mvc-496 Figure 45 8. 5. SINGLE SPEED BEVEL GEAR TRANSMISSION 9. The bearing, bearing retainer, HOC plate, spring arm, and pivot arm all come off as one unit (Figure 46). Transmission Disassembly 1. Remove 4 screws holding the cover on the transmission. The axle, bearings, and bevel gear can be lifted out (Figure 48). Figure 46 mvc-480 10. To disassemble the spring/pivot arm assembly, compress the components with two clamps or locking pliers (Figure 47). The snap ring can now be removed. Loosen the clamps with care due to the spring arm tension. Separate the spring arm components. Figure 75 shows the parts disassembled. Figure 48 2. mvc-462 Since the pulley was previously removed, the input shaft will now slip out of the transmission case. If the input bearing is to be removed, press it out of the case now. 3. Figure 47 mvc-478 Walk Behind Power Mower Drive Systems Manual 3-5 SINGLE SPEED BEVEL GEAR TRANSMISSION 4. Slide the bearings and thrust washer off the axle. Drive the roll pin out and the bevel gear can be removed (Figure 49). 2. Install the thrust washer on the side of the gear with the shorter hub, away from the gear teeth (Figure 51). Figure 49 Transmission Assembly Assemble in reverse order. Assembly Tips 1. mvc-468 Figure 51 3. mvc-468 Install the transmission bearings with the flange facing the gear (Figure 52). The same axle is used for both front and rear drive versions. There are two holes in the axle about one inch apart. Front wheel drive transmissions use the hole in the axle that is about 5¾” (14.6cm) from the end or closest to the center of the axle (Figure 50). Slip the gear on such that the teeth and the longest hub face the center of the axle. Drive the pin into place. A double check is that neither of the pin holes should be visible when the gear is installed. Figure 52 4. 5. 6. mvc-470 If the input bearing was removed, press the new one in until it bottoms in the case. Fill the transmission case approximately 2/3 full with #2 Lithium base grease. Assemble the bearing, bearing retainer, Height Of Cut plate, spring arm, and pivot arm. Use two clamps or vise grips to compress the assembly so the snap ring can be installed. NOTE: Install the snap ring with the sharp edge facing away from the spring arm. Figure 50 mvc-466 3-6 Walk Behind Power Mower Drive Systems Manual SINGLE SPEED BEVEL GEAR TRANSMISSION 7. Coat the axle, key, and spring with #2 molybendum disulfide base grease or anti-seize compound before installing the pinion (Figure 53). Belt Service - Front Wheel Drive Models To replace the self-propelled drive belt, proceed as follows: 1. 2. Drain the fuel and oil and tip the mower on its right side. Remove the two screws securing the belt cover from under the housing (Figure 55). Figure 53 8. mvc-472 The wheel pinion is marked with an R and L for right and left. Identify right and left from the operator’s position (Figure 54). On the right side, the letter R should face out. The letter L should face out on the left side. If the wheel pinions are reversed, the wheels will not drive. 3. Figure 55 mvc-482 Slip the belt off the transmission pulley and push it towards the engine (Figure 56). Figure 54 mvc-474 Figure 56 mvc-487 Walk Behind Power Mower Drive Systems Manual 3-7 SINGLE SPEED BEVEL GEAR TRANSMISSION 4. Remove one of the mounting screws for the belt guide and loosen the other. DO NOT bend the belt guide (Figure 57). The blade can be removed, but it is not required for belt replacement. REAR WHEEL DRIVE MODELS Transmission Removal and Belt Replacement On rear wheel drive models, it is necessary to separate the rear drive assembly from the mower housing in order to change the drive belt. 1. 2. Drain fuel and oil from the engine. Remove the single retaining screw from the center of the bag door spring. Slide the door to one side and remove it from the rear HOC side plates (Figure 59). Figure 57 Blade removed for clarity. 5. mvc-490 Slip the belt out of the crankshaft pulley and over the blade (Figure 58). Figure 59 mvc-733 Figure 58 Reverse the process to install a new belt. mvc-491 3-8 Walk Behind Power Mower Drive Systems Manual SINGLE SPEED BEVEL GEAR TRANSMISSION 3. Remove the plug from the hole next to where the SP cable goes through the chassis (Figure 60). Pinch the fitting on the end of the cable and slide the cable into the hole where the plug was just removed. Special tool (Part #105-6819) works nicely for this (Figure 61). Slip the tool over the cable on the underside of the mower. Press the end over the fitting on the end of the cable. The tool will depress the tabs on the cable, allowing it to be removed from the housing. 5. If desired, remove the stop cable from the engine (Figure 61) and disconnect the SP cable spring from the transmission. Pinch the ends of the lower handle together to disengage them from the pins on the HOC plates (Figure 62). If the SP and stop cables were not disconnected, set the handle so that the cables will not get kinked while working on the mower. Figure 62 Figure 60 mvc-735 mvc-737 6. 7. Tip the mower onto its right side (carburetor up) and remove the blade. Remove one of the belt guide screws and loosen the other enough to pivot the guide away (Figure 63). Do not bend the belt guide. Slide the pulley/ blade adapter and belt off the crankshaft. A Figure 61 dsc-017 (A) Cable tool (P/N 105-6819) - shown being used on stop cable for clarity 4. Remove both rear wheels and both wheel covers. Figure 63 mvc-738 Walk Behind Power Mower Drive Systems Manual 3-9 The belt cover must be removed in order to remove the belt (Figure 66). Figure 66 Figure 64 9. Place the mower right side up and remove the three hex head and one Allen head cap screws on each side that hold the Height Of Cut plates to the chassis (Figure 64).SINGLE SPEED BEVEL GEAR TRANSMISSION 8. Remove 3 screws that secure the belt cover to the housing (Figure 67).10 Walk Behind Power Mower Drive Systems Manual . Figure 67 Figure 65 mvc-744 mvc-852 3 . 10. The transmission assembly will now drop down. mvc-743 mvc-848 11. There is a cross brace underneath the mower that is held in place by two of these cap screws. 11 . 14. The pulley must be lifted off slightly to slip the belt off. The cable may be unhooked from the arm on the transmission to help prevent cable damage (Figure 70). Remove the retaining rings and thrust washers that secure the pinions to the axle (Figure 71). install a new one now. If the belt only is to be replaced. Reverse the process to assemble. Rear Axle Disassembly 1. Figure 69 mvc-740 Figure 71 mvc-746 Walk Behind Power Mower Drive Systems Manual 3 . Figure 68 mvc-745 13. Do not bend the belt guide. Clamp the axle with locking pliers and remove the pulley nut and transmission pulley (Figure 69). Note: It is not necessary to remove the transmission to replace the control cable.SINGLE SPEED BEVEL GEAR TRANSMISSION 12. Pull the belt towards the crankshaft and remove. Pull the belt cover out from under the rear wall and the belt is exposed (Figure 68). If other transmission repairs are necessary proceed as follows. Figure 70 mvc-741 15. spring arm and pivot arm (Figure 75). This includes the bearing. 6. 3. HOC plate. note that there is a spring-loaded key under them. spring arm. Remove the other thrust washer and retaining ring holding the pivot assembly to the axle (Figure 72). Remove the washer and gear cover. Clamp the pivot assembly with 2 pairs of locking pliers or other clamps and remove the snap ring (Figure 74). 5. When removing the pinions. bearing retainer. Figure 75 Figure 73 mvc-747 mvc-750 3 .12 Walk Behind Power Mower Drive Systems Manual . mvc-850 mvc-748 (A) Snap Ring 7. The pivot assembly will slide off the axle. You can now release the clamps an separate the HOC plate. A Figure 74 Figure 72 4.SINGLE SPEED BEVEL GEAR TRANSMISSION 2. and pivot arm (Figure 73). and bevel gear can be lifted out (Figure 76). The axle. mvc-462 Since the pulley was previously removed. press it out now. Slip the gear on such that the teeth and the longest hub face the short end of the axle. If the input bearing is to be removed.SINGLE SPEED BEVEL GEAR TRANSMISSION Transmission Disassembly 1. A double check is that neither of the pin holes should be visible when the gear is installed. Figure 77 MVC-470 Figure 79 mvc-469 Walk Behind Power Mower Drive Systems Manual 3 . There are two holes in the axle about one inch apart (Figure 78). Figure 78 mvc-469 Install the thrust washer on the side of the gear with the shortest hub. the input shaft will now slip out of the transmission case. Rear wheel drive models use the hole about 4¾” (12cm) from the end. 3. Remove the 4 screws holding the cover on the transmission. Transmission Assembly Assemble in reverse order. Slide the bearings and thrust washer off the axle. 2. Drive the roll pin out and the bevel gear can be removed (Figure 77). bearings. Drive the pin into place.13 . away from the gear teeth (Figure 79). Figure 76 2. 4. Axle Assembly Tips 1. The same axle is used for both front and rear wheel drive models. spring arm. Figure 82 mvc-474 WHEEL PINION SERVICE The steps to service the wheel pinions are the same for both front and rear wheel drive models. On the right side. 3 . Use two vise grips or clamps to compress the assembly so the snap ring can be installed (Figure 80). Remove the wheel bolt and wheel and wheel cover (Figure 83). If the wheel pinions are reversed. bearing retainer. Identify right and left from the operator’s position (Figure 82). and spring with #2 molybendum disulfide grease or anti-seize compound before installing the pinion (Figure 81). and pivot arm. Install the transmission bearings with the flange facing the gear. Figure 80 6. MVC-748 Coat the axle. the wheels will not drive. MVC-739 Remove the retaining ring and thrust washer. 1.SINGLE SPEED BEVEL GEAR TRANSMISSION 3. The letter L should face outward on the left side. 2. 4. NOTE: Install the snap ring with the sharp edge facing away from the spring arm. key. support with a block. Figure 81 mvc-472 Figure 83 3. The wheel pinion is marked with an R and L for right and left. the R should face outward. 5. Raise the mower until the wheel is off the ground. 7.14 Walk Behind Power Mower Drive Systems Manual . Fill the transmission approximately 2/3 full with #2 Lithium base grease. Assemble the bearing. HOC plate. mvc-850 (B) Key Behind the pinion should be another thrust washer and retaining ring (Figure 84). 2.15 . 3. A B Figure 84 (A) Retaining Ring & Thrust Washer 5. Figure 87 mvc-753 Figure 85 mvc-472 Walk Behind Power Mower Drive Systems Manual 3 . Note: there is a spring-loaded key under the pinion (Figure 84). 22” STEEL DECK TRACTION ADJUSTMENTS Bail Control 1. m-5660 Reassemble in reverse order: 1. Place a 1. Lubricate the axle.75” (4. key. then the first retaining ring with the sharp edge facing the chassis (Figure 85). Slide the wheel pinion off the axle. Figure 86 2.5cm) spacer between the bottom of the upper handle and the top of the traction bail (Figure 86).SINGLE SPEED BEVEL GEAR TRANSMISSION 4. and spring with #2 molybendum disulfide base grease or anti-seize and install the pinion (Figure 85). Lift traction bail so that it contacts the spacer. Remove cable slack and tighten cable clamp (Figure 87). Install one thrust washer. To adjust the cable. Figure 88 2. However. it will be necessary to reach under the deck and rotate the gearbox forward until the bracket contacts the rear baffle.16 Walk Behind Power Mower Drive Systems Manual . Note: This is the same adjustment process as the other Toro Personal Pace and Lawn-Boy Easy Stride systems. the gearbox on this mower is not visible from the top of the deck. Rotate gearbox forward until gearbox bracket contacts stop on rear baffle (Figure 88).SINGLE SPEED BEVEL GEAR TRANSMISSION Personal Pace 1. mvc-752 Remove cable slack and tighten cable clamp (Figure 89). Figure 89 mvc-754 3 . 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 6 Description Pinion-25T Pinion-20T Gear-15t Spur. 1 1 1 1 1 2 1 1 1 1 1 1 1 1 2 Description Bushing .Key. 21 22 23 24 26 27 28 29 30 31 32 34 36 37 38 Qty. Shift Shaft .Thrust Bushing Bushing . No. Shift Key .Output Collar .Flat Bearing .Shift Walk Behind Power Mower Drive Systems Manual 4-1 .Pinion. Gear Screw .Case.Fork.Tapping Ref.THREE SPEED TRANSMISSION GEARCASE ASSEMBLY Ref.Shift Clip . Upper Cover . 37t Bevel Washer .Output Yoke .Yoke Retainer .Shift Spacer Pulley .Output Washer Gear-49 T Gear-44 T Gear-39 T Sleeve .Spring Shaft .Intermediate Case .Ball Bushing . 1 2 3 4 5 8 9 11 12 13 14 15 17 18 19 20 Qty.Spring Sleeve .Lock NI Washer .Half Gear .Gear Pin .Gear. Bevel Nut . No. both top and bottom. these three gears rotate freely on the gear sleeve. When the operator squeezes the control bar toward the handle.8 mph (6. Figure 90 3428-0196 Speed Reduction System: Speed reduction is accomplished by two sets of gears--one set on the intermediate shaft and the other set on the output shaft.9km/h) 2. that gear will rotate the output shaft.5 mph (4. Once the key engages one of the gears. The gear sleeve is coupled to the output shaft with a roll pin so the gear sleeve always rotates with the output shaft. Tensioning of the belt is accomplished by pivoting the transmission.9km/h) 2. The gears on the intermediate shaft are powdered metal and ride on a hexagonal shaft supported on each end by oil impregnated bushings. however. The shift fork is supported. The self-propel pulley at the engine is keyed to the crankshaft.8 mph (2. Table 1 shows approximate speeds in gears for two different engine speeds. The pulley on top of the transmission is supported by a ball bearing and drives a pinion gear inside the transmission. a control cable tilts the transmission backward and tensions the belt. A E B C D Figure 91 (A) Intermediate Shaft & Gears (B) Bevel Gear 3428-0058 (C) Shift Key (D) Gear Sleeve (E) Output Shaft & Gears There are also three gears on the output shaft. These gears are driven by the pinion at the bottom of the input shaft. The driven bevel gear turns the shaft so that all three gears on the intermediate shaft have the same rotational velocity (Figure 91).8 mph (2. 4-2 Walk Behind Power Mower Drive Systems Manual . When the control bar is released. These keys engage one of the three gears that rotate on the gear sleeve. gravity pivots the transmission forward to loosen the belt.2 mph (1. Belt guides at the engine pulley and atop the transmission ensure disengagement by forcing the belt to loop around the engine pulley (Figure 90).3km/h) The shift keys are retained on one end by the shift collar.THREE SPEED TRANSMISSION OPERATION Input System: Power is transferred from the engine to the transmission by a belt. This determines the final drive ratio. The gear selection system determines which one of these three gears will be coupled with the gear sleeve and the output shaft.1km/h) Ground Speed @ 2000 RPM 1. Gear Selection System: Gear selection is determined by moving sliding shift keys in a sleeve that is fixed to the output shaft. by nylon bushings for smooth operation and long wear (Figure 92).9km/h) 1.7 mph (4. Movement of the shift fork positions the shift collar and shift key.4km/h) 3. Table 1 Gear 1 2 3 Ground Speed @ 3000 RPM 1. THREE SPEED TRANSMISSION A B C C Figure 92 (A) Gear Sleeve (B) Shift Collar (C) Keys 3428-0065 Figure 93 (A) Screen Panel (B) Screws 4. 1. This will make it easier to remove the speed selection cable later. Remove the two flanged head self-tapping screws securing the screen panel to the housing and remove the panel (Figure 93). Loosen the gear selection control cable clamp screw until the cable comes free.Toro Vacu Power/Lawn-Boy Medallion Models Complete transmission removal on the Toro Vacu Power/Lawn-Boy Medallion mower is quite easy and is recommended for most self-propel system repairs. 5. 7. Removal . 3. Walk Behind Power Mower Drive Systems Manual 4-3 . and drain the fuel and oil. (C) Transmission Access Cover The operator controls movement of the shift fork by means of the gear selection control and cable. Pull the cable from belt guide and remove the belt guide. Remove the two flanged head self-tapping screws securing the belt cover to the top of the transmission. Do not attempt to remove the gear selection cable from the control arm at this time. Remove the transmission access cover from the rear of the housing by pressing from underneath. 6. Remove the spark plug lead from the engine to prevent accidental starting. Remove the black plastic transmission cover from the top rear of the housing. Place the ground speed selector in neutral. 2. NOTE: There are no shift detents in or on the transmission on 1988 and newer mowers. Slowly pull the transmission from the housing being very careful not to damage the gear selection cable. Remove 4 self-tapping screws securing end caps to housing (Figure 94). the gear reduction system and gear selection system. 2. 3428-0121 1. 4. Pivot both spring arms until they point straight down. Disassembly Inspection of this transmission can be accomplished without removing the pivot arm assembly from the output shaft. Turn the mower onto its right side and remove the four flanged head self-tapping screws securing the end caps to the housing (Figure 94). Remove the six flanged head self-tapping screws securing the transmission cover to the transmission case and remove the cover (Figure 95). Remove the belt cover. Only if components on the output shaft require replacement will pivot arm removal be necessary.THREE SPEED TRANSMISSION 8. rotate the assembly until the cable can be safely removed. Remove both rear wheels and wheel covers. 2. Remove belt cover and belt.1). Slide the pivot arm and spring arm off the axles. Figure 94 (A) End Cap 9. raise the rear and support it with blocks. Slide the transmission to the right to slip the short end of the axle out of the chassis.2. For more information on this. Before disassembling further. 1. A 3. Remove the rocking key clutches (see "Wheel Pinion Clutch" on page 5 . Once clear of the housing. check for proper operation of the input system. 2.Recycler/Rear Bagger Chassis To remove the transmission from the chassis. 4. Removal . 4-4 Walk Behind Power Mower Drive Systems Manual . 3. Disconnect shift and clutch cables. Loosen the belt guide and slip the belt off the pulley. Disconnect shift and clutch cables. refer to ”OPERATION" on page 4 . Alternate Method 1. Figure 95 3428-0120 5. Inspect all parts for wear and damage and replace if necessary. the spacer. Apply a light coat of lithium-based grease on the output shaft under the output bushing. and on the the three output shaft gears. 8. Assemble from the end of the shaft closest to the hole for the roll pin. Replace any parts necessary. Remove the three output shaft gears from the output shaft.THREE SPEED TRANSMISSION 3. 7. cracks. Slide the three output shaft gears onto the gear sleeve.3. Slide the output bushing onto the output shaft. 2. (177cc) No. tabs last and secure with a new roll pin. When assembling. the shift keys and spring clip. Walk Behind Power Mower Drive Systems Manual 4-5 . Output Shaft Assembly 1. Inspect all gears for wear. Drive out the roll pin securing the gear sleeve to the output shaft and remove the gear sleeve and remaining output shaft bushing. A B 9.Disassembly" on page 5 . and the shift key sleeve from the output shaft. and/or broken teeth. it is not recommended since inspection of the inside of the output gears is not possible. and inspect all components for wear or damage. NOTE: A cut-away transmission cover can be fabricated to hold the intermediate shaft in place to facilitate pulley nut removal. 3. Inspect the bushings for excessive wear. notched sides last. If service of any of the output shaft gears or the gear selection system is required. Figure 96 4. 3428-0058 10. Slide the gear sleeve onto the output shaft. Transmission .Assembly The transmission uses 6 oz. This situation can be addressed by using an impact wrench or by removing the 20 (B) and 25 (A) tooth gears (Figure 96) from the intermediate shaft and then putting the intermediate shaft assembly back onto the transmission. However. be sure to coat all moving components with grease to ensure proper lubrication. Remove the cotter pin from the top of the shift fork and remove the shift lever. Remove the intermediate shaft from the transmission and clean. flanged side last. on the gear sleeve. Be careful not to lose the two spacers that fit between the bevel gear and the bushing. Carefully pull the output shaft from the transmission case. remove the left pivot arm as described under "Rear Height-Of-Cut And Wheel Pinion Clutch . If ball bearing replacement is required. 5. 2 lithiumbased grease as a lubricant. The hexagonal intermediate shaft can then be held with a 7/16” end wrench while the pulley nut is loosened. Check the input shaft ball bearing for roughness or excessive drag and replace any parts necessary. clean. the shift collar. 6. press the ball bearing out using an arbor press. Removal of the input shaft and pulley assembly can be difficult because the input pinion will have a tendency to turn as the pulley nut is loosened. Pull the output shaft bushing. NOTE: It is possible to replace the shift keys and spring clip without removing the pivot arm if the roll pin securing the gear sleeve to the output shaft is first driven out. A B Figure 97 (A) Output Shaft 5. and spring clip for assembly as shown in Figure 98. (B) Shift Key Sleeve 8. 4-6 Walk Behind Power Mower Drive Systems Manual . press a new one into the gearcase using an arbor press. Input Shaft Assembly 1. Press only on the outer race or bearing damage may result. shift collar. onto the output shaft. If the input bearing was removed. Don’t forget to coat these components with a light coat of grease (Figure 99).THREE SPEED TRANSMISSION 4. large end first. Slide the nylon shift key sleeve onto the output shaft. 3428-0065 Slide the shift key assembly into the shift key sleeve until the shift collar bottoms out. flanged side first. Make sure that it engages the tabs on the gear sleeve (Figure 97). reassemble now as described under "Rear Height-Of-Cut and Wheel Pinion Clutch Assembly" on page 5 . Figure 99 3428-0066 Coat the shift key sleeve with grease and prepare the shift keys. 7. If the left pivot arm was removed for servicing. Figure 98 6. Complete the output shaft assembly by sliding a spacer washer and the other output bushing.4. Slip the shift fork into the slot on the shift collar and place the shift fork and output shaft assembly into the transmission. Apply a light bead of lithium-based grease to flange. (C) Ball Bearing (D) Pinion 1. Figure 100 (A) Pulley (B) Spacer 3. then secure the shift fork with the white nylon shift fork retainer (Figure 101). A C Figure 101 (A) Intermediate Shaft (B) Flange B 3428-0059 (C) Shift Fork Retainer Intermediate Shaft Assembly NOTE: Before assembling. under Disassembly. 2 lithium-based grease. NOTE: The long end of the shift fork shaft should go through the hole in the gearcase. The input pulley nut can be tightened after complete transmission assembly. Note that the larger output bushing goes on the longer end of the shaft and the shorter output bushing goes on the shorter end of shaft. 4. page 4 . or at this point using the process in step 3.4. flanged end first (Figure 102). Slip an intermediate shaft bushing onto the left end of the intermediate shaft. Make sure that the output bushings are trapped in the proper locations. Install a flat washer and a nylon locknut finger tight. Figure 102 (A) Bushings (B) Gears (C) Spacers Walk Behind Power Mower Drive Systems Manual 4-7 .THREE SPEED TRANSMISSION 2. Slide the input shaft and pinion through the ball bearing and assemble the spacer and two pulley halves as shown in Figure 100. Slide the yoke bushing onto the lower end of the shift fork. coat the intermediate shaft with No. 5. THREE SPEED TRANSMISSION 2. Figure 103 3428-0196 4-8 Walk Behind Power Mower Drive Systems Manual . Slide the intermediate shaft gears onto the intermediate shaft in this order: • 25-tooth gear • 20-tooth gear • 15-tooth gear/bevel gear 3. Torque the belt guide fasteners to 130 in. making sure that the end caps are on the outside of the housing. Before securing. Installation For assembly. 6. Drop the intermediate shaft into the gearcase. Place the transmission and pivot arm assembly into the deck. 5. Fill the gear case with 6 oz. Secure the input pulley nut. (15 N·m) (Figure 103). Slip the gear selection cable into the shift fork shift lever through the bottom as shown in Figure 104. Bring the transmission assembly into position underneath the deck. Slide 2 spacer washers onto the intermediate shaft next to the bevel gear and follow with an intermediate shaft bushing. (177cc) of No. 4. 3428-0123 Special Assembly Notes For Toro Vacu Power/ Lawn-Boy Medallion 1. reverse the removal process. flanged side first. making sure that all gears engage properly. 3. 2 lithium-based grease. lbs. then install the cover with the six flanged head self-tapping capscrews. Loosely install the two front end cap fasteners. Figure 104 2. install the shift fork control arm onto the shift fork and secure with the cotter pin. THREE SPEED TRANSMISSION 4. Tighten all four end cap fasteners (Figure 105). Slip the traction belt into position on the transmission pulley. If dried grease or dirt keeps the keys from rocking up and down. Slip the two rear end cap fasteners through the safety shield guide wires then install. Ibs. Walk Behind Power Mower Drive Systems Manual 4-9 . along with a loud bang each time. Slip the end of the traction cable into the belt guide bracket from the outside. (26 N·m) TROUBLESHOOTING TIPS . the keys might be slipping. Then check at the shift arm for free movement where it enters the transmission. Ibs. A Figure 105 (A) End Cap 5. then pause and lurch again. Install the upper BBC cover with the two flanged head self-tapping capscrews. Unless gear teeth are broken off. 3428-0122 6.3 SPEED TRANSMISSION Hard Shifting A raised boss molded into each gear causes the leading edge of the key to depress before it can enter the next gear (Figure 106). Make sure that the top edge is trapped underneath the lip of the housing. The ring on the shift collar end of the key holds the drive end of the key up. (15 N·m) 7. If the wheels lurch forward. Then install the belt guide bracket onto the top of the transmission. Belt Guide Fastener Torque: 130 in. Slip the black plastic transmission cover into place making sure that the belt falls in the appropriate grooves. the force required to shift gears will increase. Check the cable for free movement. making sure that the traction belt is inside the guide. These are quick checks and should be made before opening the transmission. Figure 106 Slipping Gears 3428-0067 The actual gears are in constant mesh. they cannot slip. Make sure that it does not bind on any of the bosses. End Cap Fastener Torque: 225 in. it can lower enough to disengage from the notch in the gear (Figure 108). replace the keys and if this occurs only with one gear. It must tighten sufficiently to fully drive the transmission.10 Walk Behind Power Mower Drive Systems Manual . if due to wear the force tries to depress the key. insert the end of the cable in the shift arm and slip the end of the cable jacket into the bracket (Figure 109). This grab and slip process causes the banging. Excessive wear to the tip of the key or the notch in the gear may be the problem (Figure 107). replace that gear also. A B Figure 109 3428-0196 Figure 107 (A) Shift Collar 3428-0065 The traction control cable tilts the transmission backward to tighten the belt and engage the transmission (Figure 110). The gear will rotate until the key lines up with the next notch and will engage it for a short time. If the forces push straight on the key.THREE SPEED TRANSMISSION Look at the key and the notch in the gear that it engages. it will drive the axle. yet allow the transmission to rock forward and loosen the belt to disengage. At minimum. To install the shift cable. However. (B) Shift Keys A C B A D Figure 110 Figure 108 (A) Gear (B) Key B 3428-0195 (C) Good Gear and Key (D) Worn Gear and Key 4 . Cable Adjustment The shift cables are not adjustable. To adjust turn the knob or loosen the cable clamp and slide the cable jacket up or down and secure with the clamp.11 . The objective is to have the wheels begin to drive when the bail is about 1” (25mm) below the upper handle. A Figure 111 (A) Clamp 3428-0043-2 Figure 112 (A) Blade Brake Cable (B) Jam Nuts Figure 113 Walk Behind Power Mower Drive Systems Manual 4 . jam nuts. yet be able to lower the bail enough to stop the wheels without releasing the bail (Figure 113). or a clamp to the handle (Figure 111 and Figure 112).THREE SPEED TRANSMISSION The adjustment point for this cable is a knob. 12 Walk Behind Power Mower Drive Systems Manual .THIS PAGE INTENTIONALLY LEFT BLANK 4 . 1 1 1 1 2 2 2 2 1 1 1 2 4 4 2 2 1 1 Description V–Belt Lever–Shift Pin–Cotter Clamp–Cable Cap–End O-Ring Spring Arm ASM Pivot Arm ASM Bushing Bushing Fitting–Zerk Washer–Arm. Keyed Ring–Klip Ring–Friction Washer–Clutch Key–Rocking. 1 2 3 4 5 6 7 8 8:2 8:3 8:4 9 10 11 12 13 14 *15 Qty. LH Key–Rocking. No. Pivot Washer–Thrust. 2 2 2 2 2 2 1 2 2 2 2 Description Gear–Pinion Spring–Compression Cover–Wheel Spacer–Cover. Wheel Wheel ASM Bushing Screw–HH Knob–Arm Screw–HH Nut Bolt–Shoulder * Not Illustrated WPM Drive Systems Manual 5-1 .Wheel Pinion Clutch WHEEL PINION CLUTCH GEARCASE AND WHEEL ASSEMBLY Ref. 16 17 18 19 20 20:1 22 23 24 25 26 Qty. No. RH Ref. it causes the pinions to move with the output shaft and drives the wheels. Clutch Washer . Wheel Pinion . If an E-clip is substituted. Three.fits in a circular groove in the pivot arm and works with the clutch washer to actuate the key.fits in corresponding recesses on the pivot arm to protect pivot arm from premature wear. That slight rotation is all that is necessary to raise the wheel pinion key and engage the pinion. One.fits in a groove on the output shaft to retain the pivot arm and spring arm.causes the wheel pinion to turn with output shaft when up. Pivot Arm . It can be rotated in the end cap to change heightof-cut. Allows the wheel pinion to “free-wheel” when down. I. Externally Tabbed Thrust Washer . when the transmission is engaged. H. it provides differential action to allow easy turning and excellent maneuverability. G. premature failure of the wheel pinion clutch system will result. The wheel pinion is a powdered metal part and is symmetrical so that it can be put on either way and still function properly. L I K 5-2 WPM Drive Systems Manual . Wheel Pinion Key . Wheel pinion turning forward “wipes” key down. Special Retaining Clip . C. Engagement with the output shaft is controlled by the wheel pinion key. This slight back and forth rotation actuates the wheel pinion key. A B D E F H J C G Figure 115 A. It does not rotate. It is also allowed to rotate slightly with respect to the output shaft.WHEEL PINION CLUTCH Wheel Pinion Clutch: The wheel pinion clutch has a three-fold purpose. Internally Tabbed Thrust Washer .turns when the operator squeezes the handle to provide power to the wheels. Two. Friction Ring .is affixed to the output shaft by means of the key so it turns with the output shaft. Clutch washer brings key up. E. Output Shaft . Friction between the clutch washer and friction ring causes the clutch washer to lag the output shaft slightly once it is engaged. This washer rotates with the output shaft and protects outboard clutch components from wear.provides support for the output shaft with a bushing and a needle bearing. There is a left-hand and right-hand key. F. B. Figure 114 3428-0028 Figure 115 shows a breakdown of the wheel pinion clutch system.positively engages the wheel gear at all times. (This is not an E-clip!) The tab at the center of the clip is extended and fits in the keyway of the output shaft to prevent rotation. D.internal tab fits in the keyway on the output shaft. it disengages the wheel pinions from the output shaft when the operator is not squeezing the handle. This allows the wheels to turn backwards without turning the gears inside the transmission and provides low pullback forces similar to those on a hand-push version (Figure 114). Check all components at this time for damage and wear. make sure that the O-ring seal is present and intact. Remove the special retaining clip at the end of the output shaft and pull off the following six wheel pinion clutch components: • Spring • Internally Tabbed Thrust Washer • Wheel Pinion • Wheel Pinion Key • Clutch Washer • Friction Ring 7. Compression Spring . L. Special Retaining Clip .fits in the outer groove on the output shaft to retain the outer wheel pinion clutch components (note that this is not an E-clip!). Pay particular attention to the grooves at the end of the output shaft. K. The wheel pinion clutch is a durable system. Greasing regularly will prevent contaminants from damaging or wearing the system. Replace it if necessary (Figure 116). Some models do not have this O-ring groove. constant.7cm) in from the end of the shaft. Rear Height-Of-Cut And Wheel Pinion Clutch Disassembly The rear height-of-cut system and the wheel pinion clutch can be serviced with the transmission in or out of the unit. 6. Substituting an E-clip will result in reduced wheel pinion clutch life. and the wheel pinion clutch components. wheel cover. Internally Tabbed Thrust Washer . Replace parts as necessary. it is extremely important that it be maintained according to the instructions in the operator’s manual. and nylon locknut.provides the light. spacers. 1. the bearing surfaces on the output shaft. inward force necessary for proper clutch washer and friction ring engagement. 8. WPM Drive Systems Manual 5-3 . which is greasing every 25 hours with one or two pumps of grease. The extended tab at the center of the clip fits into the keyway to prevent rotation with respect to the output shaft. 4. However. see Transmission . Removal of the grease fitting is not recommended because it is pressed in. if damaged or lost.Removal. however. For information on removing the transmission from the unit. 2. Figure 116 3.turns with the output shaft to prevent wear problems between the spring and the wheel pinion. This seal is important to keep grease in and contaminants out. Check the innermost groove on the output shaft which is located 2-1/4” (5. Remove the shoulder bolt securing the wheel and tire assembly to the pivot arm and remove the wheel and tire assembly complete with shoulder bolt. Disconnect the spark plug lead from the spark plug to prevent accidental starting.WHEEL PINION CLUTCH J. Press the needle bearing and the oil impregnated bushing from the pivot arm using an arbor press. Remove the inner special retaining clip from the output shaft and remove the following components: • Internally Tabbed Thrust Washer • Externally Tabbed Thrust Washer • Pivot Arm and Spring Arm Assembly • End Cap (if desired) 5. we suggest tapping and installing a threaded grease fitting. This will prevent rotation of the clip on the output shaft. Place the wheel pinion key in the groove on the output shaft with the leg toward the clutch washer. 5-4 WPM Drive Systems Manual . Figure 117 (C) Key (D) Spring Arm 3428-0028 To increase service life.060” (1. 11. 6. then press into the outside of the pivot arm until it is flush with the groove that houses the externally tabbed thrust washer. but do not fasten at this time. then pull the knob straight off. Assemble the spring arm and pivot arm as shown in Figure 117. 3. Rear Height-Of-Cut and Wheel Pinion Clutch Assembly 1. 2. A B C D (A) Pivot Arm (B) Friction Washer 5. Press the oil impregnated bushing into the boss on the pivot arm until it is flush with the face of the boss.7cm) in from end on each output shaft. 12. Slide the clutch washer onto the shaft so that the recesses for the key are facing out. Place the friction ring into the groove on the pivot arm. Slide the pivot arm and spring arm assembly onto the output shaft. making sure that the center tab fits properly into the keyway. install new O-rings in the innermost groove 2-1/4” (5. making sure that it is fully seated in the groove.5mm). Install the spring arm knob so that the concave side of the knob and the convex side of the rivet align. 9. NOTE: There is a left and a right wheel pinion key. push in on the detent tab.) Secure with the special retaining clip. 10. boss first. You are using the correct key if. 8. NOTE: The convex side of the spring arm rivet and the concave side of the knob on the spring arm should both be facing the housing. Refer to Figure 117. (Make sure that the tab on the internally tabbed thrust washer enters the keyway. 4.WHEEL PINION CLUTCH 9. make sure all parts are clean prior to assembly and coated with new grease. If spring arm disassembly was required. Slide the externally tabbed thrust washer and the internally tabbed thrust washer onto the output shaft. If the spring arm knob requires replacement. 7. the top of the key is flat and the straight portion of the leg is perpendicular to the shaft. install the knob making sure that the detent is pressed out about . NOTE: The detent rivet is not replaceable. flat side out. Not all models have this O-ring groove. Slip the end cap onto the output shaft. If removed. when placed in the groove. Pack the caged needle bearing with grease. 17. Place the wheel pinion onto the output shaft. Slip the spring onto the end of the output shaft and secure with the special retaining clip. make sure that the center tab fits properly into the keyway to prevent rotation of the clip (Figure 119). use two pumps to ensure that you do not overgrease. Use a hand grease gun to avoid excess pressure that may prevent the friction parts from working. 15. 16. rotate the clutch washer back and forth slightly. 2 lithium-based grease. Install the internally tabbed thrust washer onto the output shaft making sure that the tab enters the keyway. As a rule. It is symmetrical and can be put on either way. Slip the wheel.WHEEL PINION CLUTCH Before assembling further. making sure that the key actuates properly (Figure 118). and the wheel cover onto the shoulder bolt and secure to the pivot arm using the nylon locknut. the original number of spacers. Figure 119 3428-0040 WPM Drive Systems Manual 5-5 . 14. Grease with No. Be sure to grease after every 25 hours of use for maximum service life. Again. Figure 118 3428-0028 13. THIS PAGE INTENTIONALLY LEFT BLANK 5-6 WPM Drive Systems Manual . and on many models. When the control is released. In order to engage the blade. the idler with the brake pad backs away from the brake drum and tightens the belt. Figure 122 Notice that position 3 is approximately 5” (12cm) below the handle.BLADE BRAKE CLUTCH SYSTEMS (BBC) There are two versions of the BBC system. The combination idler arm and brake controls the belt. It does this by tensioning and loosening the BBC cable. the traction drive is integrated with this control system. Clutch Operation The clutch operates by using a flywheel which turns with the engine crankshaft and a brake drum and blade that are free to turn separately from the flywheel. then raise the control bar to position 3. the control bar can be lifted to the handle without affecting operation of the BBC system. The normal or “at rest” position of the control bar is indicated by the number 1 in the Figure 122. When the control is engaged. The handle controls are the same for both and the parts that mount on the crankshaft are the same. Refer to the BBC cable adjustment section for proper adjustments. The difference is in the linkage on top and under the deck that engages and disengages the blade drive. be sure that it is adjusted properly. the operator must first “cock” the control bar down to position 2. On units without self-propel. Control Box Operation The BBC control mechanism’s purpose is to actuate the deck mechanism. This distance between position 3 and the handle is reserved for engagement of the transmission on those models equipped with self-propel. a spring causes the idler to pivot towards the brake drum releasing the belt and engaging the brake. then with the separate deck systems. Figure 120 3428-0001 Figure 121 3428-0004 Before troubleshooting the BBC deck mechanism. One is used on the Toro Vacu Power and Lawn-Boy Medallion mowers (Figure 120) and the other on the Toro Recycler and Rear Bagger mower chassis (Figure 121). This stops the blade but allows the flywheel and crankshaft to continue to turn. The two are connected by tensioning a drive belt between the flywheel and brake drum. Walk Behind Power Mower Drive Systems Manual 6-1 . This section will deal with the common control system. The control mechanism meets the federal government’s “2-step” blade engagement procedure. It is affixed solidly to the control arm by means of the roll pin. These components interact to provide control to the BBC deck mechanism. Figure 123 a. Transmission is engaged when cable is tightened. d. The spring is flexed or “buckled” when the control bar is operated. Control Bar: Pivots on upper shoulder bolt. This is the “at rest” position. BBC Cable Lever: Controls tensioning and loosening of the BBC cable since the end of the BBC cable is retained by it. on self-propel models. BBC Cable: Transfers inputs from the control box to the BBC deck mechanism. Traction Lever: Provides input to the traction cable since the end of the traction cable Is retained in it. Pivots freely on the upper carriage bolt. Houses both the control hook and cable lever. release of the control bar disengages the blade and. Leaf Spring: Releases control hook as control bar drops to “at rest” position. the transmission. By gradually releasing the control bar. h. Also provides slot and stop for buckling spring. it is the buckling spring that supports it. Buckling Spring: Sole purpose is to hold the control bar in the middle position when at rest. c. g. e. f. both the BBC and the transmission are disengaged. Control Hook and Spring: Pivots on the roll pin and is spring-loaded in the counterclockwise direction by the torsion spring. 6-2 Walk Behind Power Mower Drive Systems Manual . Notice in Figure 124 the position of the traction cable lever and the BBC cable lever. disengaged when cable is loosened. Also pivots on the upper shoulder bolt when the control bar is moved. Traction Cable: Engages transmission by transferring inputs from the control box. k. The control hook “grabs” the cable lever when the control bar is cocked and releases the cable lever when the control bar is dropped. b. Right Control Housing: Serves as other half of control box cover. Houses leaf spring. the operator can regulate the ground speed of selfpropel models without disengaging the blade. Left Control Housing: Serves as cover for BBC control mechanism. it allows the control hook to slip by as the control bar is raised. Also houses end of traction and BBC cables. Because of orientation. When the control bar is in this position. Transfers operator inputs to control box components. Handle Controls The control box components and their functions (Figure 123) are described below. Notice that the buckling spring is not flexed and is at the left end of the slot in the rocker arm. i. Movement is controlled by the control hook. Rocker Arm: Pivots on the upper carriage bolt. j.BLADE BRAKE CLUTCH SYSTEMS (BBC) After engagement of the blade. It rides in a slot on the rocker arm to prevent it from applying force to the control bar when the control bar is at its lowest or uppermost positions. BLADE BRAKE CLUTCH SYSTEMS (BBC) D When the control bar is raised to a point 5” (12. The spring-loaded control hook slides over the cable lever and grasps it so that when the lever is raised.7cm) below the handle. the BBC cable will come with it. Also important is the function of the leaf spring. A C B Figure 124 (A) Buckling Spring (B) Traction Cable Lever 3428-0278 (C) BBC Cable Lever (D) Control Hook A When the control bar is cocked to its lowest position as in Figure 125. Continuing to raise the control bar causes the traction lever to move and the traction cable engages the transmission. Raising the control bar straightens the buckling spring. a number of events take place. the left tip of the control hook slips by the leaf spring without causing release of the cable lever. B Figure 126 (A) Control Hook 3428-0289 A B C Figure 125 3428-0286 (A) Rocker Arm (B) BBC Cable Lever (C) Control Hook Walk Behind Power Mower Drive Systems Manual 6-3 . The buckling spring is flexed and moves in the end of the rocker arm slot to the right end. The other event takes place inside the rocker arm. As the control bar is raised. the BBC cable has been tightened enough to engage the blade (Figure 126). 6-4 Walk Behind Power Mower Drive Systems Manual . (A) Leaf Spring 6. Determine if any of the components inside the control box are malfunctioning. However. NOTE: The cable ends and end of the spring are not retained once the right cover is removed. thereby causing the BBC to declutch and brake the blade (Figure 127). Remove the BBC cable from the BBC cable lever and the left-hand control box half. Figure 128 3428-0289 3. Bend the locking tab securing the throttle control to the control panel. Reinstall the flange nuts to help hold things together. Carefully remove the 2 flange nuts retaining the control box to the handle and remove the right control box half. C B A The first and quickest method is to manually hold the ends of the cable and the end of the buckling spring while operating the control bar. all components will function normally. Be careful not to dislodge any internal components.BLADE BRAKE CLUTCH SYSTEMS (BBC) When the control bar is released. remove the right housing half. 5. 7. 1. Be sure to use one the two methods below to retain them. 3428-0290 Figure 127 (A) Leaf Spring (B) Flange Nut Control Box Disassembly (C) Contact Point A better method is to make a special cut-away version of the right control box housing half as shown in Figure 128. Instead. NOTE: When servicing the BBC control box. the leaf spring is no longer in place and you will not be able to observe release of the BBC cable lever. then tap the throttle control out using a rubber mallet. See Step 5 below for more information. the tip of the control hook catches on the leaf spring causing it to rotate. with the right case half removed. then operate the control box while watching for proper function of internal components. remove the buckling spring and washer from the rocker arm assembly. CAUTION! Wear gloves and eye protection when operating an open control box as the buckling spring could fly out. This releases the BBC cable lever. be careful not to disassemble the unit any further than necessary as it will then become difficult to troubleshoot. This will aid in diagnosis. Notice the cut-away cover and how it houses the leaf spring. If further disassembly is required. Place a piece of duct tape over the heads of the carriage bolts passing through the handle and the BBC control box. When this cut-away version is installed. This will prevent them from falling out later during troubleshooting. Remove the 3 flanged head screws retaining the 2 control box halves. A 2. 4. This will aid in assembly. Slip the end of the traction cable into the traction lever. Remove the cable lever from the rocker arm assembly. 11. and the control bar into position as shown in Figure 129. 5. Walk Behind Power Mower Drive Systems Manual 6-5 . Inspect all parts for wear and/or damage and replace as required. Slide the sleeve onto the upper carriage bolt making sure that it passes through the control bar. (C) Traction Cable Figure 131 (A) BBC Cable Lever (B) BBC Cable Place a piece of duct tape over the heads of the carriage bolts that slide through the handle and the left control box housing. complete with cable lever and control hook. 14. Press the roll pin from the rocker arm and remove the control hook and torsion spring. Release the BBC cable lever from the control hook and install the BBC cable into the cable lever (Figure 131). the control hook and the cable lever will be engaged. Pull the tape from the outside of the handle and remove the upper carriage bolt and the cable lever and spacer with it. the traction lever. and the left control housing. Control Box Assembly 1. Remove the rocker arm as an assembly. slide the carriage bolt through all three components. Also loosely install the BBC cable lever as indicated. Remove the traction cable from the traction lever and the left-hand control housing. 13. Figure 130 (A) Control Hook (B) Roll Pin Flush With This Side 6.BLADE BRAKE CLUTCH SYSTEMS (BBC) 8. Then place the control housing. Remove the lower carriage bolt and remove the left control housing. Position the control hook and torsion spring in the rocker arm as shown in Figure 130. When correctly installed. Also make sure that the roll pin passes through the hole in the control bar. Slip the lower carriage bolt through the handle. 4. 7. 10. Secure with the roll pin making sure that the roll pin is flush with the side indicated in the Figure. NOTE: The BBC cable lever is behind the spring. Once in position. Figure 129 (A) Control Bar (B) Traction Lever 3. 2. 12. (C) Cable Lever Slide the rocker arm assembly over the upper carriage bolt and sleeve making sure that the sleeve passes through the cable lever. 9. then slide the left control housing onto it. traction lever. 13. Also make sure that the sleeve passes through all components including the left control housing.BLADE BRAKE CLUTCH SYSTEMS (BBC) 8. Check for proper operation of the entire BBC system. Install the 3 flanged head screws that retain the two control box halves. Correct as required. 12. 10. Install the right control housing and secure with the 2 nylon locknuts or 1 locknut and 1 flange nut. Slip the spring into position in the rocker arm and the left control housing as shown in Figure 132. (B) Buckling Spring Assemble the right control housing by installing the leaf spring and pin to retain the leaf spring (Figure 133). B A 11. Slip the white nylon washer onto the J end of the buckling spring. The slotted side of the washer should face away from the end of the spring. Figure 132 (A) Nylon Washer 9. Finally. Before installing the right control housing. make sure that the roll pin passes through the rocker arm and control bar. check to make sure that both cable sheath ends are fully seated in their slots in the left housing. Adjust the BBC cable and traction cables as needed. Bend the throttle control locking tab forward to provide positive lock with the throttle control and install the throttle control. A Figure 133 (A) Leaf Spring mvc-488 6-6 Walk Behind Power Mower Drive Systems Manual . 3428-0281 14. BLADE BRAKE CLUTCH SYSTEMS (BBC) TORO BBC SERVICE GUIDE Disassembly Sequence 1 2 3 Walk Behind Power Mower Drive Systems Manual 6-7 . No. No. 22 23 24 25 26 27 28 31 32 33 34 35 36 37 38 39 42 43 44 45 46 Qty.BLADE BRAKE CLUTCH SYSTEMS (BBC) BLADE BRAKE CLUTCH ASSEMBLY (Toro Vacu Power Lawn-Boy / Medallion BBC) Ref. 1 1 1 1 1 1 2 1 1 1 1 1 1 2 1 1 2 1 2 1 1 Description HH Screw Compression Spring Spring Retainer Woodruff Key Driver Pulley BBC Flywheel Blade Bolt Brake Drum Hub ASM BBC Shield Blade Spacer 21” Blade Anti Scalp Cup Lock Nut Lock Nut BBC Screen Vibration Damper Idler Pulley HH Screw Thd Forming Screw Flat Washer 6-8 Walk Behind Power Mower Drive Systems Manual . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Qty. 1 1 1 2 2 1 1 1 1 1 1 1 1 5 1 1 2 1 1 1 1 Description Brake Shoe Plate Hub “V” Belt Pulley Hub Lock Nut Spring Rod Shoulder Bolt Compression Spring Flange Bushing Lever Wa Bushing Ring Seal HWH Screw TAP Screw Flange Nut Cable Bracket Support Flat Washer Bellcrank Bushing Crank Spring Pin Control Link Ref. A C B Figure 134 3428-0079 Figure 136 (A) Shoulder Bolt (B) Bellcrank 4. Once loose. 3428-0082 Bellcrank System Disassembly (Toro Vacu Power/ Lawn-Boy Medallion) 1. Pull the black plastic transmission cover up to remove it from the housing (Figure 135). Remove the flanged head self-tapping capscrews securing the upper BBC cover to the housing and remove the upper BBC cover (Figure 134). Remove the shoulder bolt and flanged nut securing the bellcrank to the control cable bracket.BLADE BRAKE CLUTCH SYSTEMS (BBC) TORO VACU POWER LAWN-BOY/ MEDALLION BBC 2. Walk Behind Power Mower Drive Systems Manual 6-9 . (C) Control Link 3428-0090 Remove the bushing from inside the bellcrank. dsc-068 Figure 135 3. remove the bellcrank assembly complete with control link and remove from the unit (Figure 136). Insert the control pin into the recessed area on the bellcrank. slip the shoulder bolt through the hole in the cable bracket support and secure with the flanged nut. 2. 3. NOTE: The serrations in the flanged nut must fully seat on the control cable bracket. Finally. Using the control link to hold the control pin. Place the spring retainer onto the spring and insert the screw into the control pin. Place the spring onto the control pin. Remove the control link from the control pin. Figure 137 3428-0093 6. CAUTION! Always wear safety goggles and gloves when disassembling Items under spring tension or compression. 5. 6.10 Walk Behind Power Mower Drive Systems Manual . Hook the end of the control link into the brake plate lever. 7. Make sure that it is installed correctly into the bellcrank. 6 .BLADE BRAKE CLUTCH SYSTEMS (BBC) 5. Note the orientation of the control link in Figure 138. C B 33428-0088 (C) Shoulder Bolt (D) Control Link (E) Brake Plate Lever Slide a flat washer and a bushing onto the shoulder bolt and slide into the front side of the bellcrank as shown in the Figure 138. D Figure 138 (A) Cable Bracket Support (B) Bellcrank 4. Complete reassembly of the bellcrank system by sliding another flat washer onto the carriage bolt. Inspect all parts for wear and damage and replace as necessary. NOTE: Lubrication of the bushing is not recommended. E A Bellcrank System Assembly (Toro Vacu Power/ Lawn-Boy Medallion) 1. Check adjustment of the BBC cable as described under “BBC Cable Removal (Recycler/Rear Bagger)” on page 6 . then slip the BBC control cable onto the bellcrank. tighten the flanged head screw until the retainer bottoms out on the control pin (Figure 137).24. Using the control link to prevent rotation of the control pin. remove the flanged head screw from the control pin (Figure 137). sharp edge down. and adjust as necessary. NOTE: It may be necessary to push the transmission back slightly to get the transmission cover to slide in completely. Figure 139 (A) BBC Flywheel (B) Brake Drum (C) Bearing Block (D) Screen Under Deck Components Disassembly (Toro Vacu Power/Lawn-Boy Medallion) 1. when properly adjusted. Slide the black plastic transmission cover into place making sure that the belt slides into the grooves provided. Place the upper BBC cover into position on the housing and secure with the two self-tapping flanged head capscrews. 8. Check for proper operation of all controls. 9. correct by adjusting the BBC control cable. If spring measures more than 1-1/4” (32mm). The screen (Figure 139) is installed. Drain fuel. especially the BBC.11 . This venting improves the airflow underneath the deck thereby improving quality of cut and bagging performance. especially if quality of cut or bagging performance has degraded. Some contact between the belt and the cover may be evident.BLADE BRAKE CLUTCH SYSTEMS (BBC) 7. Stop the engine and disconnect the spark plug lead to prevent accidental starting. Be sure to clean the screen on occasion. BBC Cover and Screen: The BBC cover and screen are two important components that keep dirt and debris out of the BBC mechanism. Walk Behind Power Mower Drive Systems Manual 6 . It should measure 1” (25mm) with the blade engaged. to allow air to be drawn in through the screen panel on top of the deck and down underneath the deck. NOTE: The spring length on the bellcrank assembly is the primary indicator of proper BBC adjustment. Before disassembling further. Pivot the brake plate counterclockwise slightly and remove the bearing block and brake drum from the crankshaft (Figure 142). use a large screwdriver or bar to wedge the BBC flywheel while removing the nut (Figure 141). Figure 141 mvc-724 4. then raised. Repair or replace parts as required. the blade. 5. However. or premature bearing failure could result. 6 . Make sure that the belt loosens properly when the control bar is lowered. Figure 142 7. Remove the 2 flanged nylon locknuts securing the blade to the bearing block and remove the antiscalp cup. begin by removing the crankshaft nut.12 Walk Behind Power Mower Drive Systems Manual . mvc-726 Again. and the lower BBC screen (Figure 140). if you must remove it manually. NOTE: Be careful not to damage the bearing seal when removing this nut. check to make sure that the BBC components are functioning normally. the blade spacer.BLADE BRAKE CLUTCH SYSTEMS (BBC) 2. Make sure that the brake and brake drum fully disengage when the control bar is cocked. and remove the lower BBC cover. 6. 3428-0099 Remove the 4 flanged head self-tapping screws securing the lower BBC cover to the housing. Figure 140 3. pivot the brake plate counterclockwise and remove the BBC flywheel. If further disassembly is required. An impact wrench works best. Make sure that the BBC flywheel and the brake drum rotate together when the control bar is raised. 13. it can be done without removal of the brake plate.BLADE BRAKE CLUTCH SYSTEMS (BBC) 8. self-tapping capscrew. If the brake pad has reached its service life or if the brake plate has been damaged. BBC Belt or Idler Pulley Replacement: If the BBC belt or idler pulley requires replacement. Complete disassembly of the brake plate by removing the brake plate screws and the bearing block. Remove the brake plate and hub assembly from the housing and disassemble the seal/oil impregnated bushing. 11. Remove the idler pulley capscrew and nylon locknut then pull the belt and pulley from the brake plate as an assembly. however. Walk Behind Power Mower Drive Systems Manual 6 . NOTE: Do not use an air wrench on the brake lever self-tapping screw as thread damage to the housing may result. Heavy gloves and eye protectIon are recommended when removing the brake plate lever. Remove the two bearings from the bearing block by pressing the bearings out on an arbor press. remove the flanged head capscrew securing the brake lever and hub to the housing. Be careful not to lose the plastic bushing which fits on the end of the brake spring rod (Figure 143).13 . the hub. If necessary. 14. The brake pad is not replaceable separately. Press only on the outer race to prevent bearing damage (use an appropriately sized arbor or a 1-1/8” (28mm) socket. and washer from the brake lever. 9. B A Figure 143 (A) Plastic Bushing (B) Brake Rod 3428-0106 12. Inspect all parts for damage and/or wear and replace as necessary. NOTE: The hubs of the pulley are replaceable. 10. remove the other capscrew securing the brake plate to the brake plate hub and lever and remove the brake plate assembly. CAUTION! The brake plate lever is under moderate spring-loading. the bearing inside the idler pulley is not replaceable separately. (25. Secure with the carriage bolt and nylon locknut as shown in Figure 145. Install an idler hub into each side of the idler pulley bearing. do not helicoil. 3428-0108 Figure 145 (A) Bolt (B) Brake Plate 3428-0101 (B) Brake Plate Bushing 5. Loosely secure the brake plate. 3. complete with brake pad. rather. (11. install the bushing hub and flanged head self-tapping screw with washer through the brake lever. to the brake lever and brake hub as shown in Figure 145. Idler Pulley Bolt Torque: 100 in. then stretch onto the brake plate bushing (Figure 144). place a hex nut in the recess provided in the top side of the deck. This will allow proper alignment of the idler pulley later. Ibs. A A B B Figure 144 (A) Seal 2. 6 . Place the spring and the bushing onto the brake rod then slip the bushing and brake rod through the hole provided in the brake lever. Check to make sure that the brake plate seal is in good condition.14 Walk Behind Power Mower Drive Systems Manual .BLADE BRAKE CLUTCH SYSTEMS (BBC) Under Deck Components Assembly (Toro Vacu Power/Lawn-Boy Medallion) 1. Ibs. Brake Plate Capscrew Torque: 225 in. Slip the entire assembly between the brake plate and brake lever. Finally.33 N·m) Hook the control link in the slot on the brake lever. Make sure that the idler pulley spins freely. 4. Tighten the idler pulley bolt. Note that the bolt should go through the brake plate first. then slip the belt onto the idler pulley. Secure with a nylon locknut but do not tighten at this time.5 N·m) NOTE: If the self-tapping screw strips the threads in the housing. Press the bearings into the bearing block. the flywheel can be wedged to tighten the nut. and the anti-scalp cup onto the BBC screws and secure with the two flanged nylon locknuts. using an arbor press. making certain that the slots in the BBC flywheel align with the bumps on the bottom of the selfpropel pulley (Figure 146). 7. Press only on the outer race. Make sure that the foam rubber anti-vibration pads are in place on the brake drum and assemble the brake drum bearing block and BBC screws onto the crankshaft as shown in Figure 148.15 . Install the BBC flywheel onto the crankshaft. lbs. Figure 148 Crankshaft Nut Torque: 61 . premature belt wear. 9.) NOTE: Make sure that the blade bolts are properly aligned before tightening the crankshaft nut. A 8. Ibs. mvc-726 A Figure 147 (A) Boss 3428-0116 10. (37 N·m). CAUTION: As with disassembly. the blade spacer. Secure with the crankshaft nut. the boss at the bottom of the keyway on the self-propel pulley will break and the self-propel pulley will be free to slide up and down on the crankshaft (Figure 147). B Figure 146 (A) Bumps (B) Slots 3428-0117 NOTE: If the crankshaft nut is tightened with these bumps misaligned. Install the BBC cover with the four flanged head self-tapping screws. the blade. Ibs. Make sure the bumps in the self-propel pulley stay engaged with the flywheel or the pulley will be damaged.95 N·m (45 .BLADE BRAKE CLUTCH SYSTEMS (BBC) 6.70 ft. Install the BBC screen. Torque to 300 in. (37 N·m) Walk Behind Power Mower Drive Systems Manual 6 . and belt jumping. Blade Locknut Torque: 300 in. otherwise bearing damage will result (use an appropriately sized arbor or a 1-1/8” (28mm) socket to press the bearing into the block). This can result in noisy operation. 3. 4. the end of the BBC cable sheath has two protruding ears that catch the underside of the cable bracket. Then install the end of the cable sheath in recess provided in the left control housing half (Figure 150). 6 .BLADE BRAKE CLUTCH SYSTEMS (BBC) 11. making sure that all are functioning normally. Complete BBC service by checking BBC and selfpropel controls. then pulling the cable out vertically. Slide a new BBC cable into the BBC cable lever.16 Walk Behind Power Mower Drive Systems Manual . make sure that the traction and BBC ends are completely seated in their recesses. Place a piece of duct tape over the heads of the handle and the BBC control box. Bend the throttle control locking tab forward so that it will provide positive engagement with the throttle control. NOTE: The flanged locknut fits on the upper carriage bolt. Secure with two nylon locknuts. BBC Cable Removal (Toro Vacu Power/Lawn-Boy Medallion) 1. Slip the end of the BBC cable from the cable lever and remove the cable (Figure 150). Adjust as necessary. Remove the three flanged head screws securing the control box halves. 2. Remove the two flanged head self-tapping screws securing the screen panel to the housing and remove the screen panel as shown in Figure 149. 3. 6. This will prevent control box components from falling out of the handle during disassembly. Remove the cable by squeezing the ears together. Bend the throttle control locking tab back slightly and tap the throttle control from the control panel with a rubber mallet. Before installing the right control housing half. make sure that the roll pin in the rocker arm passes through the hole in the control bar. Later models use a clip that must be pushed to the side to remove. Remove the two nylon locknuts securing the control box to the handle and carefully remove the right control housing half. (B) Screen Panel 3428-0079 On early models. 4. Figure 150 (A) BBC Cable (B) BBC Cable Lever A A B BBC Cable Installation (Toro Vacu Power/Lawn-Boy Medallion) 1. Install the throttle control. Install the three flanged head screws securing the control box halves. Install the right control housing half. Figure 149 (A) Screws 2. Also make sure that the sleeve on the upper carriage bolt passes completely through the BBC control box components to the handle. Finally. 5. 6. Walk Behind Power Mower Drive Systems Manual 6 . (C) Spring Before installing the screen panel. which follows. Install the screen panel with the two flanged head self-tapping screws. Otherwise proceed with adjustment in the following step. Remove the two flanged head self-tapping screws securing the screen panel to the housing and remove the screen panel. especially if quality of cut or bagging performance has degraded. Tighten the jam nuts by turning them in opposite directions. Then slip the cable through the slot in the cable bracket. adjust the BBC cable as described under “BBC Cable Adjustment (Toro Vacu Power/Lawn-Boy Medallion Models)”. Remove the tape from the handle and disengage the blade. Make sure that the top edge of the screen panel is under the lip at the top of the housing. Be sure to clean the screen on occasion. This venting improves the airflow underneath the deck thereby improving quality of cut and bagging performance. then measure the length of the over-travel spring (Figure 151). 2. With the engine off and the spark plug wire disconnected. Continue adjustment until the overtravel spring measures 1” (25mm).BLADE BRAKE CLUTCH SYSTEMS (BBC) 5. skip ahead to step 5. Hook the lower end of the BBC cable onto the bellcrank. 3. cock and lift the control bar to engage the blade. (B) Jam Nuts BBC Cable Adjustment (Toro Vacu Power/LawnBoy Medallion Models) 1. Loosen the two jam nuts in the middle of the BBC cable as shown in Figure 152. it should measure 1” (25mm). Figure 151 (A) Plastic Fitting (B) Cable Fitting 6. Push the end of the cable sheath into the cable support bracket as shown in Figure 151. NOTE: On 1990 and newer BBC cables use a finger tip adjustment at the gearbox end.17 . Tape the control bar to the handle with the blade engaged. Rotate the nuts up to make the spring shorter or down to make the spring longer. When adjusted properly. to allow air to be drawn in through the screen panel on top of the deck and down underneath the deck. sharp edge down. If it does. The screen (Figure 153) is installed. 5. Figure 152 (A) Blade Brake Cable 4. Cock the bail downward and raise to the handle. but the gap isn’t so large that the handle is hard to hold (Figure 154).18 Walk Behind Power Mower Drive Systems Manual . On BBC models. Excessive cable tension causes the control hook in the control box to release. If the BBC disengages and you hear the brake engage with a snap. This measurement is not an exact requirement. the cable is likely too tight. the control bail also controls the transmission belt engagement. 6 . Ideally.BLADE BRAKE CLUTCH SYSTEMS (BBC) Figure 153 (A) BBC Flywheel (B) Brake Drum (C) Bearing Block (D) Screen Figure 154 NOTE: An overly tight cable will cause the BBC to disengage before the bail can be raised to the normal operating position. It can be varied to accommodate a customer with small hands. etc. the cable should be set so that the transmission drives well and will disengage when the bail is lowered about 1” 1-1/2” (3. This allows the bail to be lowered so that the wheels stop driving and the BBC remains engaged. Loosen the cable slightly and repeat the test. It doesn’t do any permanent damage to any parts. The adjustment point is a knob where the cable enters the transmission cover or an adjusting turnbuckle in the cable.8cm). No.BLADE BRAKE CLUTCH SYSTEMS (BBC) ENGINE AND BLADE ASSEMBLY (Toro Recycler / Rear Bagger) Ref. No. 1 1 1 1 1 1 3 1 1 1 1 2 1 2 1 1 1 1 1 1 1 2 Description Gts Ohv 200 Engine Gas Cap ASM Toro Nameplate Recoil Decal Clamp Screw Casing Clamp HWH Screw Belt Guide Bracket Woodruff Key Pulley Flywheel Blade Bolt Brake Drum ASM Vibration Dampener Hub ASM Shield Blade Spacer Blade Nut Recycler Blade Blade Stiffener Anti–Scalp Cup Lock Nut Ref. 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Qty.19 . 1 2 1 1 1 1 1 1 1 2 1 1 1 1 1 1 2 3 2 1 Description HH Screw Flat Washer Control Link Bellcrank Bellcrank Sleeve Lever HH Screw Torsion Spring Washer Bearing Torsion Spring Brake ASM Idler Pulley V Belt Idler Hub Pulley HH Screw NI Lock Nut HWH Screw HH Screw Rope Stop Walk Behind Power Mower Drive Systems Manual 6 . 1 2 3 4 5 6 7 8 9 10 11 12 13 13:1 14 16 17 18 19 20 21 22 Qty. but leave it engaged at this time (Figure 158). Figure 155 3428-0174 Figure 157 3428-0182 6 .BLADE BRAKE CLUTCH SYSTEMS (BBC) TORO RECYCLER / REAR BAGGER BBC 3. loosen the clamp that secures the BBC cable to the mower housing. the idler arm can pivot away from the brake drum and the belt can be removed. On the left side of the mower next to the rear wheel.20 Walk Behind Power Mower Drive Systems Manual . and unhook the control link from the lever (Figure 155). B Figure 156 (C) Spring 3428-0177-2 2. Take a loop of wire or rope and unhook the spring under the lever (Figure 156). Drain the fuel and oil. C (A) Screwdriver (B) Wire Loop 4. Remove the spark plug wire. sleeve. Remove the blade and the BBC cover. A 1350-001 Idler Arm System Disassembly (Recycler/Rear Bagger) 1. We would suggest loosening this screw. Remove the screw. Note the pulley is on the deck side and there is a spacer between the pulley and idler arm (Figure 157). unhook the spring end of the cable from the bellcrank. Locate the idler arm. With the tension removed you can now remove the long screw through the lever. With the pulley removed. Turn the mower on its side. Disassembly for the idler arm begins on top of the mower housing. Brush any grass clippings out of the area. Near the left front wheel. bellcrank. Remove the bolt and locknut that retains the idler pulley. 21 . Now reach around to the top of the housing and pull the screw out of the lever (Figure 158). the large nut on the crankshaft can be spun off. Slide the lever off the shaft and the idler/brake shaft can be pulled down and out of the housing (Figure 159). This will hold the crankshaft so the nut can be removed.) Clean the old grease out of the bearings and from the shaft. wedge a bar or large screwdriver into the BBC flywheel (Figure 161). disassemble the components on the crankshaft. Press them out at this time (Figure 160). Figure 158 3428-0179 Figure 161 Figure 159 3428-0192 3428-0187 Walk Behind Power Mower Drive Systems Manual 6 . If you have an impact wrench.BLADE BRAKE CLUTCH SYSTEMS (BBC) 5. If you must remove it manually. The bushings and bearings are not interchangeable. 3428-0185 Now. If they are to be replaced. (Note that early models of this system used a bushing instead of bearings. A Figure 160 (A) Bearings 6. There are two bearings pressed into the housing that the idler shaft rides on. 9. The flywheel is pressed onto a taper on the crankshaft. when the nut on the crankshaft is tightened. the pulley will bounce up and down during use and make a rattling noise (Figure 163). A B Figure 162 8. Inspect the pulley.22 Walk Behind Power Mower Drive Systems Manual . The two bumps on the pulley should face you (Figure 164). One end of the keyway is blocked off. Usually this is caused by an error in assembly. Refer to “Idler Arm System Assembly (Recycler/Rear Bagger)” on page 6 . Start by installing the key and self-propel pulley. the pulley must be replaced. The two bumps on the pulley MUST engage the holes in the flywheel. If that is broken. (A) Bumps 2. There are two bumps on the outside of the pulley that are intended to engage two holes in the flywheel. If this wall is broken out or the bumps on the pulley are damaged. the flywheel will push the pulley upwards. It might require a tap with a hammer to loosen (Figure 162). Slip the belt over the this pulley.22 for instructions to avoid this. Figure 164 3428-0117 (B) Holes in Flywheel Install the flywheel. Figure 163 3428-0116 6 . If not. 3428-103 Roll the self-propel belt off the pulley and remove the pulley and the key in the crankshaft. Idler Arm System Assembly (Recycler/Rear Bagger) 1. either breaking the wall out of the key groove or crushing the two bumps or both.BLADE BRAKE CLUTCH SYSTEMS (BBC) 7. Remove the hub assembly and brake drum. do not be concerned. it will hold the crankshaft from rotating while you tighten the nut (Figure 161). If you engage the bumps on the pulley into the flywheel. They are noise dampeners. 6. Install the brake drum. Rust on the outside is harmless. CAUTION! The two bumps on the pulley MUST engage the flywheel. Check the shaft of the idler/brake arm. an impact wrench works best. Make sure the bolts are fully seated. If you can’t push the flywheel on far enough to hold. Push the flywheel firmly on the taper of the crankshaft. mvc-727 Note the two small foam pads inside the brake drum (Figure 166). Clean as necessary and apply a light coat of grease. If the seals are damaged or the bearing feel rough when it is turned. the drum will ring like a bell. Figure 165 3. Also look at the two blade mounting bolts. 3428-0189 Inspect the hub assembly if the old one is to be reused. A Figure 166 (A) Foam Pad 3428-0188 Walk Behind Power Mower Drive Systems Manual 6 . Do NOT drive it on with a hammer. Slip the BBC belt over the parts on the crankshaft. Figure 167 4. Start the nut on the crankshaft. As during disassembly. Each has a flat side on the head to prevent them from rotating when the nut is tightened (Figure 167).BLADE BRAKE CLUTCH SYSTEMS (BBC) The flywheel must be installed with the side that looks like 1/2 of a pulley facing the brake drum (Figure 165). But the seals in the bearing need to be intact. 5. 7. you can now wedge the flywheel and through the pulley and key.23 . replace the hub assembly. Without them when the brake pad hits the drum. If you do not have an impact wrench. this is where the two bumps become important. Hold the idler/brake arm in place. BBC Cable Removal (Recycler/Rear Bagger) 1. Slip the spring over the shaft. Install the lever and install the screw through the lever and idler/brake arm shaft (Figure 170).24 Walk Behind Power Mower Drive Systems Manual . Rotate the idler/spring arm counterclockwise (Figure 169) and push the rest of the way into the housing. Figure 169 3428-0192 Figure 171 3428-0172 6 . Pull it towards you and hook the end as shown. 3428-0190 C (A) Screwdriver (B) Wire B Figure 170 (C) Spring 3428-0177-3 Start the shaft into the hole in the housing. Take a loop of wire or rope and hook the end of the spring. The brake pad should now ride on the brake drum. Slip the spring over the end on top of the deck as shown. One tang of the spring must engage the tab as shown (Figure 168). 10. Rotate the idler/brake arm clockwise so the upper tab on the spring can engage the boss in the housing. Loosen the cable clamp and pull cable out from under the screw (Figure 171). A A Figure 168 (A) Idler/Brake Arm 9.BLADE BRAKE CLUTCH SYSTEMS (BBC) 8. Once the screw is secured. Finally.BLADE BRAKE CLUTCH SYSTEMS (BBC) 2. Figure 173 (A) BBC Cable (B) BBC Cable Lever Walk Behind Power Mower Drive Systems Manual 6 . Unhook the spring and cable from the bellcrank (Figure 172). Remove the two nylon locknuts securing the control box to the handle and carefully remove the right control housing half. Slip end of cable under screw. 3. Slip the end of the BBC cable from the cable lever and remove the cable (Figure 173). Slide a new BBC cable into the BBC cable lever. Figure 172 3. 3428-0173 Bend the throttle control locking tab back slightly and tap the throttle control from the control panel with a rubber mallet. Before installing the right control housing half. This will prevent control box components from falling out of the handle during disassembly. Also make sure that the sleeve on the upper carriage bolt passes completely through the BBC control box components to the handle. NOTE: The flanged locknut fits on the upper carriage bolt. Install the three flanged head screws securing the control box halves. Bend the throttle control locking tab forward so that it will provide positive engagement with the throttle control. 2. 6. make sure that the roll pin in the rocker arm passes through the hole in the control bar.). Secure with two nylon locknuts. 6. BBC Cable Installation (Recycler/Rear Bagger) 1. 5. Hook spring on end of cable into the bellcrank arm (Figure 172). 4. Then install the end of the cable sheath in recess provided in the left control housing half (1. Install the throttle control. make sure that the traction and BBC ends are completely seated in their recesses. 4.25 . 5. Place a piece of duct tape over the heads of the handle and the BBC control box. Install the right control housing half. Remove the three flanged head screws securing the control box halves. The spring on the forward end of the cable should be suspended just off the housing.26 Walk Behind Power Mower Drive Systems Manual . This allows the bail to be lowered so that the wheels stop driving and the BBC remains engaged. Figure 174 3428-0172 NOTE: An overly tight cable will cause the BBC to disengage before the bail can be raised to the normal operating position. etc. If the BBC disengages and you hear the brake engage with a snap. Cock the bail downward and raise to the handle.BLADE BRAKE CLUTCH SYSTEMS (BBC) BBC Cable Adjustment (Recycler/Rear Bagger) The cable adjustment is the clamp on top of the housing on the left side of the mower. Pull the cable to the rear just enough to remove the slack (Figure 174). but the gap isn’t so large that the handle is hard to hold (Figure 175). the control bail also controls the transmission belt engagement. Hold and tighten the clamp. Ideally. This measurement is not an exact requirement. the cable should be set so that the transmission drives well and will disengage when the bail is lowered about 1” 1-1/2” (3. It doesn’t do any permanent damage to any parts. It can be varied to accommodate a customer with small hands. Loosen the cable slightly and repeat the test. Loosen the screw holding the cable clamp.8cm). The adjustment point is a knob where the cable enters the transmission cover or an adjusting turnbuckle in the cable. On BBC models. Excessive cable tension causes the control hook in the control box to release. the cable is likely too tight. Figure 175 6 . . 492-4733 .