If it is confirmed through troubleshooting that the bucket overturning is normal due to the hydraulic system fault and only the boom lifting is slow and weak. This shows that the working pump and the main safety valve are working normally. It also shows that the oil quantity and quality of the pipeline and oil filter at the oil inlet end of the pump as well as the oil tank are all right. At this time, it is only necessary to check the boom spool valve, boom oil cylinder, boom oil pipe and its seals. The internal leakage of the hydraulic system mainly occurs in the boom spool valve and the cylinder. Internal leakage mainly occurs in valve body and cylinder. Not easy to check. However, some auxiliary methods can be used to judge the leakage.
