Hydraulic pump repair and maintenance

Fault reason: (1) The oil level of the hydraulic oil tank is too low;
Troubleshooting: Add hydraulic oil
Reason for malfunction: (2) Failure to use hydraulic oil according to season;
Exclusion method: Usually suitable for 46 # hydraulic oil (or 68 #) without special replacement, consider using 32 # when it is extremely cold in the north in winter#
Fault cause: (3) The oil inlet pipe is severely blocked by dirt;
Exclusion method: Remove foreign objects from the tube
Fault cause: (4) The oil seal of the oil pump driving gear is damaged, and air enters the hydraulic system;
Troubleshooting: Replace aged or damaged oil seals and O-ring seals
Reason for fault: (5) The "O" shaped sealing ring of the oil pump inlet and outlet joints or bent joints is damaged, the fastening bolts of the bent joints or the nuts of the inlet and outlet pipes are not tightened, and air enters the hydraulic system;
Troubleshooting: Replace the O-ring seal and tighten the bolts or nuts at the joint
Fault cause: (6) Internal leakage of the oil pump and aging of the sealing ring;
Troubleshooting: Replace the sealing ring
Fault cause: (7) The oil pump end face or the end face of the main and driven gear shaft sleeves are worn or scratched, and the unevenness of the two shaft sleeve end faces exceeds the tolerance;
Troubleshooting: Replace the worn gear oil pump or oil pump shaft sleeve, and if there is slight wear, grind the end face flat on the flat plate. The allowable unevenness error is 0.03mm; The end face of the upper shaft sleeve is lower than the pump body and the upper plane (normal value is less than 2.5-2.6mm). If it exceeds the tolerance, the lower shaft sleeve should be compensated with 0.1-0.2mm copper plates. During installation, it should be installed on the rear shaft sleeve
Fault cause: (8) Internal leakage caused by incorrect assembly of internal parts of the oil pump;
Troubleshooting: The unloading plate and sealing ring must be installed in the oil chamber in order to maintain balance between the two shaft sleeves. The elastic force of the guide steel wire should be able to simultaneously twist the upper and lower shaft sleeves towards the direction of rotation of the driven gear by a small angle, so that the machining planes of the main and driven gear sleeves are tightly fitted; The unloading groove on the shaft sleeve must be installed on one side of the low-pressure chamber to eliminate harmful dead volume generated during gear meshing; Before pressing in the self tightening oil seal, a layer of lubricating oil should be applied to its surface, and attention should be paid to placing the oil blocking edge towards the front cover and not installing it upside down; Before installing the pump cover, a small amount of hydraulic oil must be poured into the pump casing and the meshing gear must be turned by hand