As a large-scale construction machinery, bulldozer can save a lot of manpower and material resources and accelerate the progress of the project. However, in the daily work, there are some minor problems with the bulldozer due to improper maintenance of the equipment or long-term disrepair. Method.

      1.Stop after normal use, can not start again, and no smoke is discharged.

　　The starter works normally, and it is preliminarily judged that the fault is on the oil road. When using a manual pump to pump oil, the amount of oil pumped is sufficient, and there is no air in the oil flow; the manual pump can also work quickly. It means that the oil supply is normal, there is no blockage in the oil line, and there is no air leakage. Shortly after the new purchase of the machine, the fuel injection pump (the lead seal is not removed) is less likely to fail. After reviewing the maintenance manual, it was found that the flame-out rod was controlled by a solenoid valve. Observation of the flame-out rod showed that it was not in the normal position. After being turned by hand, it started normally. It is determined that the fault is on the solenoid valve. After the solenoid valve is replaced, the engine works normally and the fault can be eliminated.

　　2. Reasons for the weakness of the arm

　　Damaged hydraulic cylinder

　　When the following failures occur in the hydraulic cylinder, such as cylinder strain, damage to the piston seal, damage to the cylinder head seal, etc., it will cause oil leakage or oil channeling, which will cause the internal efficiency of the cylinder to become smaller and the output power The smaller, the bulldozer's boom lift speed will be reduced, resulting in weakness problems;

　　Reduced hydraulic pump power

　　When the leakage of the hydraulic oil pump increases and the mechanical friction loss increases, the total power of the oil pump will be reduced, the flow of the oil pump will be reduced accordingly, and the lifting speed of the boom will also become slower;

　　3: Oil leak

　　The reason why the arm lift of the bulldozer accessories is slow is related to the oil system of the hydraulic system. When there is a problem of oil leakage, for example, the sealing of the suction section of the oil pump is poor, and the pressure section of the oil pump to the cylinder leaks oil out of the system;

　　4: Oil circuit blocked

　　When there are too many mechanical impurities in the hydraulic fluid, the impurities will block the part of the oil flow surface with a large oil flow path, the flow rate of the cylinder will be reduced, the output power of the cylinder will be reduced, and the boom lifting speed will be slower.

　　5: The bulldozer's right steering is not sensitive. After the joystick is moved, sometimes it can turn and sometimes the response is slow.

　　The bulldozer steering hydraulic system is mainly composed of coarse filter 1. steering pump 2. steering fine filter 3. steering control valve 7. brake booster 9. safety valve and oil cooler 5. The hydraulic oil in the steering clutch box passes through the magnetic coarse filter 1. It is sucked by the steering pump 2. and then sent by the pump into the steering fine filter 3. Enter the steering control valve 4. The brake booster and the safety valve. After the safety valve (set pressure 2MPa), the released hydraulic oil flows into the oil cooler bypass valve. If the oil pressure of the bypass valve of the oil cooler exceeds the set pressure of 1.2 MPa due to reasons such as clogging of the oil cooler 5 or the lubrication system, the hydraulic oil is drained into the steering clutch case. When the steering lever is pulled halfway, the hydraulic oil flowing to the steering control valve 7 flows into the steering clutch. When the steering lever is pulled to the bottom, the hydraulic oil continues to flow into the steering clutch to disengage the steering clutch, and at the same time flows into the brake booster. The brake acts as a brake.

　　Preliminarily concluded that the failure occurred in: ① The steering clutch could not be completely disengaged or slipped; ② The steering brake did not work. For 1. the reason why the clutch cannot be completely disengaged or slipped is as follows: the external cause is insufficient oil pressure to operate the steering clutch. The measured pressures at ports B and C are not much different, because the machine only has a right steering insensitivity and a left steering normal, indicating that the oil pressure is sufficient, and the fault cannot be here. The internal cause is the failure of the internal structure of the clutch. For internal causes, we have to perform disintegration checks, which are more complicated and will not be checked temporarily. For 2. there are three reasons why the steering brake does not work: ① Insufficient brake oil pressure. The measured pressure at the D and E ports is the same, which may be excluded. ② The friction plate is slipping. Since the machine is not used for a long time, the possibility of friction plate wear is relatively small. ③The braking stroke is too large, tighten with 90N·m torque, and turn back 11/6 turns. After the test machine, the phenomenon of insensitive steering to the right was resolved. At the same time, the possibility of failure of the internal structure of the clutch is also eliminated. The failure is due to the braking stroke being too large.

　　Therefore, we usually need to carry out certain maintenance on bulldozer parts, so as to extend the service life of the parts, thereby reducing the occurrence of the above situation and ensuring the normal use of the machine.