Bulldozer Troubleshooting

1. Main clutch slips
When the main clutch of a bulldozer slips, the engine speed is normal and no black smoke is emitted, and the working device works normally, but the machine has difficulty climbing and may even be unable to move. Main clutch slip is the most common fault of a bulldozer. The main reasons are: wear of the main and driven plates; welding of the lock pin of the adjustment plate; the main clutch lever is not in place; the thread engagement between the adjustment plate and the flywheel cover end is poor. Clutch slip failure is sometimes very difficult to handle. The general repairman's method of handling it is to repeatedly rotate the adjustment plate. If the clutch still slips after adjusting the adjustment plate many times, the transmission is often removed first and the main clutch is disassembled blindly. This not only fails to find the fault point but also easily damages other parts and delays production, resulting in large economic losses. For this reason, careful analysis should be carried out according to the above possible reasons during the investigation to be effective. For example, our company has a Yellow River TY220 bulldozer. The main clutch sometimes slips during operation. At the beginning, the machine can barely work by adjusting its adjustment plate, but it will not be long before the lock pin screw rod is disengaged. In this case, we have to remove the main clutch and replace the two screw rods of the lock pin with new ones. We also checked all the parts (the parts are not damaged, and the main and driven plates are basically not worn). The machine returned to normal. But after a month, the main clutch slipped again. Finally, the clutch had to be adjusted every 2 hours, making it impossible to carry out the construction. At that time, we decided to replace the whole set of main clutch, but this not only wasted money, but also was not allowed due to the busy production time. After several adjustments, the bulldozer only pushed a few or dozens of shovels before the clutch began to slip. Finally, it was determined that the screw test between the adjustment plate and the flywheel cover end was worse. Therefore, after adjusting the main clutch, the lock pin screw rod was locked with a lock nut. After this method, the machine has been used for half a year without adjusting the main clutch, indicating that the fault point has been found correctly.
2. The main clutch lever is heavy
The main reasons are: the oil filter is blocked, the oil supply is insufficient, so that the booster does not work; the main clutch hydraulic system lacks oil; the booster is damaged or the booster safety valve has problems; the bimetal sleeve in the movable sleeve is burned. When the clutch lever is heavy, you should first check whether the oil level of its hydraulic system meets the requirements; if the oil level is appropriate, you can temporarily remove the oil filter, and then pull the main clutch lever. If you feel that the lever becomes strong, it means that the oil filter is blocked. At this time, you only need to clean or replace the oil filter. If the oil circuit is normal, but the main clutch lever is heavy, you can first check whether the booster safety valve is stuck or leaking oil. If there is no problem with the booster safety valve, you must check the booster; or check whether the bimetal sleeve in the movable sleeve is burned, and it can be replaced if necessary.
3. The gear makes abnormal noise when shifting and is difficult to engage
The main reasons are: the adjustment plate is too tight; the hand brake has poor braking effect. When the adjustment plate is too tight, it is difficult for the main clutch to separate, so the power cannot be cut off, causing the gear to make abnormal noise when shifting. At this time, the adjustment plate should be adjusted counterclockwise to the appropriate position, that is, when adjusting the main clutch, as long as you can clearly hear the crisp sound when crossing the dead point when pulling the main clutch handle. If the hand brake has a poor braking effect, the main clutch will be separated, but the main clutch shaft will still rotate due to inertia (according to the requirements, when the main clutch is in the separated state, the main clutch shaft should stop within 3s), so the gears are difficult to mesh and make abnormal noises when shifting. At this time, the small brake belt must be adjusted or replaced.
4. The main clutch cannot be engaged
The main reasons are: the short pin shaft on the connecting plate falls off; the heavy hammer of the moving sleeve is installed reversely; the main clutch cover is not covered during the repair process, check whether the short pin shaft of the moving sleeve falls off and whether the heavy hammer of the moving sleeve is installed reversely (if the heavy hammer is installed reversely, the moving sleeve cannot enter the adjustment plate). If necessary, the moving sleeve can be removed, the short pin shaft can be re-riveted, and the adjustment plate can be installed. If the main clutch lever shaft is not installed in place, the lever shaft should be adjusted in place as required.