Self-judgment and maintenance of common faults of bulldozers

Bulldozers is one of the mechanical (hydraulic) equipment with relatively high technical difficulty and complicated processes in the construction machinery industry. If an excellent driver can master self-judgment and maintenance of some common faults, it will greatly improve work efficiency and prolong the life of the equipment. service life. For the common faults of bulldozers, we provide the most simple and intuitive solutions for users and drivers, and we hope to help you.

1. The oil temperature of the hydraulic torque converter is high

When this happens, judge yourself first:

1. First, check whether the amount of oil in the gearbox or rear axle box is appropriate.
2. Does the oil temperature rise when the hydraulic torque converter stalls, and drop when it is not stalled? If it is normal, it means that the speed is not selected properly.
3. Check whether the oil temperature gauge is accurate and the oil temperature is normal, but if the oil temperature gauge on the car exceeds the working area, the oil temperature gauge is inaccurate.
4. Whether the adjustment of the gearbox joystick is appropriate.

If none of the above reasons is true, then perform the following judgments and repairs according to the fault phenomenon:

1. When the oil temperature is low, the pump makes an abnormal noise. Please check whether the coarse filter is blocked and whether the suction section of the pump sucks in the air, and then clean, repair or replace it.
2. The limit speed is low when there is no load. Please check whether there is oil leakage inside the hydraulic torque converter, whether the sealing ring is bad, whether the cock is loose, etc., whether the filter for the oil return pump is blocked, and whether the oil return pump is defective. If so, please clean and repair or replace it.
3. The oil pressure at the outlet of the torque converter is low. Please check whether there is oil leakage inside the torque converter, whether the sealing ring is bad and the cock is loose, etc., and repair or replace it.
4. The oil pressure at the inlet of the hydraulic torque converter is low. Please check whether the safety valve of the hydraulic torque converter is malfunctioning and repair or replace it.
5. The pressure of the gearbox adjustment safety valve is low. Please check whether the coarse filter is blocked, whether the suction section of the pump sucks in air, and whether the pump is defective, and then clean, repair or replace it.
6. There is a large amount of oil leakage inside the torque converter. Please check whether there is oil leakage inside the torque converter, whether the sealing ring is bad and the cock is loose, etc., and repair or replace it.

2. The steering clutch cannot be disengaged

When this happens, judge yourself first:

1. First, check whether the oil quantity of the gearbox or the rear axle box is appropriate.
2. Check whether the valve stem travel is correct.
3. Is the control linkage of the steering clutch properly adjusted?
4. Is the function of the brake normal?
5. Is it suddenly impossible to separate? Please check whether the gears are burnt and the parts are damaged.
6. Is there any abnormal sound? Please check whether the parts are damaged.

If none of the above reasons is true, then perform the following judgments and repairs according to the fault phenomenon:

1. The oil pressure is low. Please check whether the filter screen of the coarse filter is clogged, the suction section of the pump sucks air, the pump is bad, the opening pressure of the safety valve is low, the seal is bad, and the seal of the central drive shaft is bad, and the seal of the clutch piston is bad.
2. When the oil pressure is low, the pump makes an abnormal sound. Please check whether the filter screen of the coarse filter is blocked or the suction section of the pump sucks in the air.
3. The clutch cannot be disengaged after the oil temperature rises, please check whether the pump is defective.
4. The oil pressure is normal but the clutch cannot be disengaged, check the steering clutch burnt.
5. Sometimes it is separated, sometimes it cannot be separated, and it cannot be joined after separation. Please check whether the valve stem action is bad.
6. The oil leakage of the clutch piston is large, check whether the sealing ring of the central transmission shaft and the sealing ring of the clutch piston are defective.
7. Only the left or right side cannot be separated, as above.
8. The steering performance is poor on flat ground or downhill. Please check whether the brake function is bad. This should also be considered when going downhill. Even if the clutch is disengaged, due to inertia, the vehicle will not turn when the brake is not used.
9. Item 7 is normal, but it cannot be separated after the oil temperature rises, check whether the pump is defective.

3. The bulldozer cannot support the car body

When this happens, judge yourself first:

1. Is the amount of oil in the working fuel tank appropriate?
2. Whether the stroke of the joystick and the valve stem of the control valve are appropriate

If none of the above reasons is true, then perform the following judgments and repairs according to the fault phenomenon:

1. When the engine is running at high speed, the oil pressure is insufficient after the bulldozing plate reaches the maximum limit. Please check whether the filter screen is blocked, the suction section of the pump sucks air, the pump is defective, the pipeline between the pump and the control valve leaks oil, and the main safety valve is opened. Low pressure, poor orifice blockage and poor sealing, poor sealing at the head end of the lifting cylinder, poor piston valve of the lifting cylinder, and poor sealing of the descending oil replenishment valve.
2. When the engine is slow, it is the same as above
3. When the engine is running at high speed, the lowering oil pressure of the bulldozing plate is insufficient. Please check whether the lifting oil supply valve is tightly sealed, the oil leakage between the control valve and the bottom end of the lifting cylinder, the sealing ring of the lifting cylinder is bad, and the piston valve of the lifting cylinder is tightly sealed. Poor, poor tightness of the descending oil supply valve
4. When the engine is at low speed, the oil pressure of the bulldozing plate is insufficient, please check that the oil chamber of the bulldozing plate of the control valve is blocked
5. Remove the pipeline at the head of the lifting cylinder. When the engine is at a slow speed and the joystick is placed in the down position, although the cylinder does not move, oil still flows out. Please check whether the sealing ring of the lifting cylinder is defective or the piston valve of the lifting cylinder is damaged. Poor sealing, poor sealing of the descending oil charge valve.

There will be a series of articles on self-diagnosis and maintenance of common faults of bulldozers in the future, so stay tuned. If your bulldozer needs any spare parts during maintenance, please contact us(CCMIE), we are selling spare parts for bulldozers of well-known domestic brands!