1. The axial clearance or radial clearance is too small. Re-adjust and repair.
2. There is dirt in the pump. Disassemble to remove foreign objects.
3. The assembly is incorrect. The machining datum plane of the two pin holes of the gear pump is not the assembly datum plane. If the pins are driven in first, and then the screws are tightened, the pump will not rotate. The correct method is to tighten the screws while turning the gear pump, and finally drill the pin holes and drive the pins.
4. The coaxiality of pump and engine coupling is poor. The coaxiality should be guaranteed within 0.1mm.
5. The parts in the pump are not demagnetized. All parts must be demagnetized before assembly.
6. The quality of the needle sleeve is unqualified or the needle is broken. Repair or replace.
7. The working oil outlet is blocked. Remove foreign objects.
