Hydraulic pump repair and maintenance

- Jun 21, 2018-

Cause of failure: (1) The oil level in the hydraulic tank is too low;

Remedy: Add hydraulic oil

Failure reason: (2) did not use hydraulic oil according to the season;

Remedy: Normally apply 46# hydraulic oil (or 68#) without special replacement. Consider using 32# when cold in the northern winter.

Cause of failure: (3) The inlet pipe is seriously blocked by dirt;

Remedy: Remove the foreign body inside the tube

Cause of failure: (4) Damage to the oil seal of the drive gear, and air enters the hydraulic system;

Remedy: Replace aging or damaged seals, O-rings

Causes of failure: (5) The “O” shaped seal ring of the oil pump inlet and outlet joints or elbow joints is damaged, the nuts of the bent joint fastening bolts or the nuts of the inlet and outlet oil pipes are not tightened, and the air enters the hydraulic system;

Remedy: Replace the O-ring and tighten the bolt or nut at the joint

Cause of failure: (6) Internal leakage in oil pump and aging of sealing ring;

Remedy: Replace the sealing ring

Cause of failure: (7) The end surface of the oil pump or the main and driven gear shaft sleeves are worn or scratched, and the unevenness of the end surfaces of the two shaft sleeves is poor;

Remedy: Replace the worn gear oil pump or the oil pump bushing. When the wear is slight, the flat surface will be ground flat. The tolerance of unevenness is 0.03mm; the end of the upper sleeve is lower than the pump body, and the upper plane (normal value is lower than 2.5~2.6mm). If it is out of tolerance, the shaft sleeve should be added with 0.1~0.2mm copper to compensate. The sleeve should be mounted on the sleeve

Cause of the fault: (8) Internal leakage in the internal parts of the pump caused by incorrect assembly;

Remedy: The unloading plate and the sealing ring must be installed in the oil chamber. The two shaft sleeves can maintain the balance. Guide wire elasticity should be able to twist the upper and lower bushings at the same time towards the driven gear in the direction of rotation by a small angle, so that the two sets of the main and driven gear bushings are closely attached to each other; the upper unloading bushing must be fitted with a low pressure chamber. Side, in order to eliminate harmful dead volume when the gear meshing; press in the self-tightening oil seal, the surface should be coated with a layer of lubricating oil, but also pay attention to the oil resistance edge toward the front cover, can not be installed reverse; before installing the pump cover, Pour a small amount of hydraulic oil into the pump casing and rotate the meshing gear by hand

Fault reason: (9) "Left-rotation" loaded "right-handed" oil pump, resulting in damage to the skeleton oil seal;

Remedy: "right-handed" pump can not be installed on the "left-handed" machine, otherwise it will damage the skeleton seal;

Cause of failure: (10) Dirty hydraulic oil.

Remedy: Clean the system and replace the hydraulic oil.

Cause of failure: (11) The filter of the pump is blocked by dirt and cannot filter oil.

Remedy: Remove dirt from the filter with a clean cleaning oil.

Cause of failure: (12) The oil level is insufficient, the suction position is too high, and the suction pipe exposes the oil level:

Remedy: Add oil to the oil level and lower the oil suction position.

Failure reason: (13) There is no paper pad on both sides of the pump body and the pump cover; the pump body is not perpendicular to the pump cover:

Remedy: Inhalation of air during rotation: A paper pad is inserted between the pump body and the pump cover; the pump body is ground on the plate with emery, so that the verticality error of the pump body and the pump cover does not exceed 0.005 mm, and the fastening of the pump body and the pump cover is connected. There must be no leakage.

Fault cause: (14) The pump's drive shaft and motor coupling are not concentric and have twisted friction:

Remedy: Adjust the concentricity of the pump and motor coupling so that the error does not exceed 0.2 mm.

Cause of failure: (15) The meshing accuracy of the pump gear is not sufficient:

Remedy: Research gear to achieve gear meshing accuracy.

Cause of failure: (16) The oil seal skeleton of the pump shaft falls off and the pump body is not sealed:

Remedy: Replace qualified shaft seal.