1. Check whether the hydraulic pump can output hydraulic oil. If it is a new hydraulic pump without hydraulic oil output, it may be that the pump body has casting defects (shrinkage cavity, sand hole, etc.), which connects the oil suction chamber and oil pressure chamber and loses the oil pressure capacity. It should be replaced by the manufacturer in time. If it is not a new hydraulic pump and there is no hydraulic oil output, the steering of the pump may be wrong, and the parts may be seriously worn or damaged. Replace them in time.

2、若液壓泵有油液輸出，查看溢流閥工作是否正常。若不正常，則可能是壓力油路中的某個閥有污物或其他原因卡住，處于回油位置，致使壓力油路與溢流回路短路，也可能是管接頭松脫，或處于壓力油路中的某些閥泄漏嚴重，或液壓缸、液壓馬達的密封損壞，嚴重泄漏。

2. If the hydraulic pump has oil output, check whether the overflow valve works normally. If it is abnormal, it may be that a valve in the pressure oil circuit is stuck due to dirt or other reasons and is in the oil return position, resulting in a short circuit between the pressure oil circuit and the overflow circuit, or the pipe joint is loose, or some valves in the pressure oil circuit leak seriously, or the seals of the hydraulic cylinder and hydraulic motor are damaged and leak seriously.

排除方法：拆開有關閥進行清洗，檢查密封間隙的大小及各種密封裝置，密封裝置損壞應更換。

Troubleshooting: disassemble relevant valves for cleaning, check the size of sealing gap and various sealing devices, and replace the damaged sealing device.

3、若液壓泵輸出流量隨壓力升高而顯著減小，且壓力達不到規(guī)定值，則是由于液壓泵磨損后間隙增大所致。

3. If the output flow of the hydraulic pump decreases significantly with the increase of pressure, and the pressure cannot reach the specified value, it is due to the increase of clearance after the hydraulic pump is worn.

排除方法：測定液壓泵的容積效率，即可確定該泵是否能繼續(xù)使用，對磨損嚴重的零件，應進行修配或更換。

Troubleshooting: determine the volumetric efficiency of the hydraulic pump to determine whether the pump can continue to be used. Repair or replace the severely worn parts.

4、若整個液壓系統(tǒng)能建立正常壓力，而某些管路或液壓缸（或液壓馬達）中無壓力，則可能是由于管路、小孔或節(jié)流閥、換向閥等部位堵塞。此時，應逐段檢查壓力和有無油液通過，找出原因，加以排除。

4. If the whole hydraulic system can establish normal pressure, but there is no pressure in some pipelines or hydraulic cylinders (or hydraulic motors), it may be due to the blockage of pipelines, small holes, throttle valves, directional valves and other parts. At this time, the pressure and the passage of oil should be checked section by section to find out the cause and eliminate it.