Troy-Bilt Bronco CRT Service Manual

Troy-Bilt Bronco CRT Service Manual

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Service Manual
Small Frame Troy-Bilt Tillers
MTD Products LLC - Product Training and Education Department
FORM NUMBER 769-01529
11/2004

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Summary of Contents for Troy-Bilt Bronco CRT

  • Page 1 Service Manual Small Frame Troy-Bilt Tillers MTD Products LLC - Product Training and Education Department FORM NUMBER 769-01529 11/2004...
  • Page 3: Table Of Contents

    TABLE OF CONTENTS Engine: ..........................1 Forward clutch cable adjustment: ..................1 Forward clutch cable assembly replacement: ..............3 Drive belt replacement: ....................5 Forward return spring replacement: ................6 Transmission removal: ....................7 Transmission disassembly: ................... 12 Transmission assembly: ....................21 Forward Idler lever Pivot: ....................
  • Page 5: Engine

    ABOUT THIS SECTION: NOTE: This section covers the Tuffy rear tine tiller, model 21A-630B063 with Serial Number 1B212G80447. This section has been techni- cally written to follow along with the Troy-Bilt Factory School. UNIT FEATURES: • 3.75 Hp, 4-cycle engine •...
  • Page 6 Troy-Bilt Small Frame Tillers 2.5. Squeeze the forward clutch bail to the upper 2.10. If the second measurement (spring coils handlebar. See Figure 2.5. extended) of the forward clutch is too long (more than 3/16”), the tension is too tight. Continue through this section.
  • Page 7: Forward Clutch Cable Assembly Replacement

    Troy-Bilt Small Frame Tillers NOTE: Rotate the forward clutch cable clock- 3.2. Loosen the hex jam nut securing the forward wise (towards the forward clutch bail) to increase clutch cable assembly to the adjustment screw tension, or counter-clockwise to decrease ten- using a 3/8”...
  • Page 8 Troy-Bilt Small Frame Tillers 3.5. Remove the lower cable tie securing the forward 3.8. Loosen the hex jam nut securing the forward clutch cable to the lower handlebar using side clutch cable to the lower cable mounting bracket cutters. See Figure 3.5.
  • Page 9: Drive Belt Replacement

    Troy-Bilt Small Frame Tillers DRIVE BELT REPLACEMENT: 4.4. Remove the belt from the engine drive pulley and forward idler pulley. See Figure 4.4. 4.1. Remove the spark plug boot from the spark plug and ground it to the engine. See Figure 4.1.
  • Page 10: Forward Return Spring Replacement

    Troy-Bilt Small Frame Tillers FORWARD RETURN SPRING REPLACE- 5.4. Remove the upper hook of the return spring from MENT: the right engine bracket using needle nose pli- ers. See Figure 5.4. 5.1. Remove the spark plug boot from the spark plug, and ground it to the engine.
  • Page 11: Transmission Removal

    Troy-Bilt Small Frame Tillers TRANSMISSION REMOVAL: 6.7. Grasp the upper handlebar and pivot the unit onto it’s nose. NOTE: Perform the Drive Belt Replacement sec- tion through forward drive belt removal, prior to 6.8. Secure the handlebar from above. performing this section. See Image Below 6.9.
  • Page 12 Troy-Bilt Small Frame Tillers 6.12. Remove the depth regulator assembly and drag 6.14. Raise the front of the tiller up until the wheel bar assembly. See Figure 6.12. assemblies are off the ground. See Figure 6.14. Depth Regulator Assembly Hood Brackets...
  • Page 13 Troy-Bilt Small Frame Tillers 6.17. Remove the forward return spring from the right 6.20. Remove both sets of hex screws securing the engine bracket using needle nose pliers. See left and right engine brackets to the transmission Figure 6.17. using a 1/2” socket. See Figure 6.20.
  • Page 14 Troy-Bilt Small Frame Tillers 6.24. Pivot the upper handlebar assembly up until the 6.28. Remove the forward return spring from the for- pulley/belt guard is flat on the floor. See Figure ward idler lever. See Figure 6.28. 6.24. Forward Pivoted Forward...
  • Page 15 Troy-Bilt Small Frame Tillers 6.30. Remove the transmission pulley, key and front 6.33. Raise the rear of the transmission up and set it support washer from the drive shaft assembly. on a 2” x 4” block. See Figure 6.33. See Figure 6.30.
  • Page 16: Transmission Disassembly

    Troy-Bilt Small Frame Tillers 6.35. Remove both large E-Clips from the right and left 7.2. Remove all four hex flange screws securing the sides of the wheel shaft using a large flat blade front transmission cover and gasket to the trans- screwdriver.
  • Page 17 Troy-Bilt Small Frame Tillers 7.6. Allow all of the gear oil to drain from the trans- 7.10. Remove the rear transmission cover gasket from mission case assembly. the transmission using a scraper. See Figure 7.10. 7.7. Rotate the transmission 180° to the right until it is in the upright position.
  • Page 18 Troy-Bilt Small Frame Tillers 7.13. Remove the rear bearing cap from the transmis- 7.18. Measure the overall thickness of the rear bear- sion housing using a scraper. See Figure 7.13. ing shims using a dial caliper. See Figure 7.18. Sealant...
  • Page 19 Troy-Bilt Small Frame Tillers 7.23. Remove the front tapered roller bearing and sup- 7.27. Remove the front tapered roller bearing race by port washer, and inspect them for wear or dam- lightly tapping on the perimeter with a small age.
  • Page 20 Troy-Bilt Small Frame Tillers 7.31. Inspect the tiller shaft assembly for wear or dam- 7.33. Remove the left and right retaining rings secur- age inside the transmission case. See Figure ing the wheel shaft in position using medium 7.31. retaining ring pliers. See Figure 7.33.
  • Page 21 Troy-Bilt Small Frame Tillers NOTE: Two paper clips with small 90° bends at 7.38. Drive the wheel shaft to the right, forcing the the end work well for external shim removal. See bronze wheel shaft bushing out of the transmis-...
  • Page 22 Troy-Bilt Small Frame Tillers 7.42. Drive the wheel shaft to the left, forcing the 7.45. Remove the Hi-Pro key from the wheel shaft bronze wheel shaft bushing out of the transmis- using a punch and a hammer. See Figure 7.45.
  • Page 23 Troy-Bilt Small Frame Tillers 7.47. Remove the left and right tine shaft oil seals from 7.49. Remove the external shims from the right and the transmission using an oil seal removal tool. left hand sides of the tine shaft using a small See Figure 7.47.
  • Page 24 Troy-Bilt Small Frame Tillers 7.52. Drive the tiller shaft to the left, forcing the bronze 7.56. Drive the tiller shaft to the right, forcing the tiller shaft bushing out of the transmission hous- bronze tiller shaft bushing out of the transmis- ing using a block of wood and a large hammer.
  • Page 25: Transmission Assembly

    Troy-Bilt Small Frame Tillers 7.61. Inspect the transmission housing for wear or 8.3. Make certain all the drive shaft components are damage. See Figure 7.61. accounted for. See Figure 8.3. Snap Ring Race Transmission Housing Tapered Roller Hex Flange Screws...
  • Page 26 Troy-Bilt Small Frame Tillers 8.5. Locate two sets of miscellaneous flat washers 8.6. Install the front snap ring using snap ring pliers. that would equal approximately.120” in thick- See Figure 8.6. ness. See Figure 8.5. Hex Flange Screws Race Miscellaneous Washers Rear Bearing Cap +/- .120”...
  • Page 27 Troy-Bilt Small Frame Tillers 8.11. Set the rear tapered roller bearing race over the 8.15. Pull the drive shaft assembly forward all the way, rear tapered roller bearing. See Figure 8.11. and set up a dial indicator at the front end. See Figure 8.15.
  • Page 28 Troy-Bilt Small Frame Tillers 8.18. Identify rear bearing cap shims that have a total 8.22. Set the rear bearing cap gasket and shim aside. stack tolerance thickness that is equal to the NOTE: The thickness of the rear bearing cap drive shaft assembly end play, minus .005”...
  • Page 29 Troy-Bilt Small Frame Tillers 8.31. If the drive shaft assembly end play is not within 8.34. Drive one of the wheel shaft’s bronze bushings tolerance, .005” to .015”, perform the above pro- into the transmission housing until it is flush with cedures again.
  • Page 30 Troy-Bilt Small Frame Tillers 8.35. Drive the Hi-Pro key into the wheel shaft using a 8.41. Drive the second wheel shaft bronze bushing soft mallet. See Figure 8.35. into the transmission housing until it is flush with the outside of the housing using a bushing driver and hammer.
  • Page 31 Troy-Bilt Small Frame Tillers 8.45. Push the wheel shaft in the opposite direction 8.49. Measure the wheel shaft end play using the until it comes to a stop. See Figure 8.45. above procedures. See Figure 8.49. Push Wheel Shaft In...
  • Page 32 Troy-Bilt Small Frame Tillers 8.58. Lubricate the insides of the wheel shaft oil seals 8.64. Drive the wheel shaft seal into the transmission with grease. See Figure 8.58. housing using a seal installation tool. NOTE: A 1” I.D. PVC pipe by 7” long works well Apply Sealant to the Outside of the Wheel Shaft Seal as a wheel seal installation tool.
  • Page 33 Troy-Bilt Small Frame Tillers 8.69. Slowly install the tine shaft through the opposite 8.74. Drive the first tine shaft bronze bushing into the bushing bore, through the tiller shaft worm gear transmission housing until it is flush with the out-...
  • Page 34 Troy-Bilt Small Frame Tillers 8.79. Split the recorded tine shaft end play, and install 8.88. If the tine shaft end play is not within tolerance, equal thickness external shims onto the wheel perform the above procedures until it is correct.
  • Page 35 Troy-Bilt Small Frame Tillers 8.96. Drive the tine shaft seal into the transmission 8.106. Set the rear bearing cap gasket, that was cho- housing using a seal installation tool. See Figure sen earlier in this section, onto the rear bearing 8.96.
  • Page 36: Forward Idler Lever Pivot

    Troy-Bilt Small Frame Tillers 8.117. Fill the transmission assembly with gear oil until 8.120. Secure the transmission covers to the transmis- it is half way up the worm gears. See Figure sion with the hex flange screws removed earlier 8.117.
  • Page 37: Reverse Clutch Cable Replacement

    NOTE: This section covers the Super Bronco Tiller, model 21A-634B063 with serial number 1B012G80125. This section has been techni- cally written to follow along with the Troy-Bilt Factory School. In addition, the Super Bronco Upper Handle Bar uses the same transmission as the Tuffy Tiller.
  • Page 38 Troy-Bilt Small Frame Tillers 1.4. Cut the cable tie securing the reverse clutch 1.7. Remove the inside jam nut securing the reverse cable to the handlebar assembly using side cut- clutch cable to the belt cover bracket using two ters. See Figure 1.4.
  • Page 39: Reverse Clutch Cable Adjustment

    Troy-Bilt Small Frame Tillers REVERSE CLUTCH CABLE ADJUSTMENT: 2.5. Adjust both hex jam nuts until the exposed por- tion of the reverse clutch cable is between 1/8” 2.1. Fully engage the reverse clutch cable using the and 1/4” when it is engaged. See Figure 2.5.
  • Page 40 Troy-Bilt Small Frame Tillers 3.3. Remove the reverse clutch cable’s Z-fitting from 3.4. Loosen the lock nut securing the reverse idler the reverse idler arm. See Figure 3.3. pulley belt guide in position using a 1/2” socket and wrench. See Figure 3.4.
  • Page 41: Reverse Idler Pulley Assembly

    Troy-Bilt Small Frame Tillers 3.8. Remove the hex screw and belleville washer REVERSE IDLER PULLEY ASSEMBLY: securing the transmission pulley to the drive 4.1. The following picture shows the reverse idler shaft assembly using a 1/2” socket. See Figure assembly components in their correct orienta- 3.8.
  • Page 42: Transmission Oil Fill Plug

    Troy-Bilt Small Frame Tillers TRANSMISSION OIL FILL PLUG: 6.1. The following picture shows the location of the oil fill plug for the transmission. See Figure 6.1. Transmission Oil Fill Figure 6.1...

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21a-630b063Pro-line crt

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