1. The hydraulic pump of the dock leveler can output hydraulic oil. If there is no hydraulic oil output, it may be that the steering of the lift hydraulic pump is not correct. The motor phase should be adjusted. If there is hydraulic oil output, each oil return pipe should be checked. If the pressure is low, tighten the pressure regulating spring of the relief valve. If the pressure still does not change, it may be that the main spool of the relief valve or the vertebral valve of the pilot part is stuck at the opening position due to dirt or rust, or the spring is broken and has no effect, or the damping hole is blocked by dirt, and the pump output The hydraulic oil immediately flows to the oil tank through the overflow valve. The method of elimination: disassemble the overflow valve, clean it, check or replace the spring, and restore its working performance.
2. The leakage of pressure oil from the high pressure chamber to the low pressure chamber may be due to the safety valve not being closed tightly, or because the piston rod or the sealing ring at the piston is damaged.
3. The oil absorption of the dock leveler is insufficient. The oil filter is blocked, and the oil filter should be cleaned or replaced.
4. The hydraulic pump is hot and the oil temperature is too high. If the hydraulic pump is damaged, a new hydraulic pump should be replaced. If the viscosity of the oil is too high, an appropriate viscosity should be selected. If the cooling is insufficient, the cooling system should be improved.
5. The speed of the hydraulic pump is too low, the belt slips, and the failure of the coupling and the prime mover should be eliminated.
6. If the output flow of the dock leveler hydraulic pump decreases significantly with the increase of pressure, and the pressure does not reach the specified value, it is caused by the increase of the gap after the pump is damaged, and it should be repaired or replaced.
7. If the entire system of the dock leveler can establish normal pressure, but there is no pressure in some pipelines or hydraulic cylinders and motors, it may be that the small holes in the pipeline, the throttle valve, the reversing valve and other parts are blocked, and the pressure and the pressure should be checked one by one. The presence or absence of oil is eliminated by finding the cause.