If the pressure of the excavator boom is low, check the internal leakage of the distribution valve

If the fault diagnosis is in the working unit hydraulic system and the boom and swing are not working properly. There are many reasons for this failure. In addition to the boom spool valve leakage and other fault causes, the main safety valve, hydraulic pump, oil filter, hydraulic oil and distribution valve inlet and return oil circuit faults may all cause this fault phenomenon. If the system pressure is low, it may be caused by leakage in the distribution valve. The following will explain how to check the internal leakage of the distribution valve. The inspection methods are different due to different models. This article is for reference only.
The main causes of leakage in the distribution valve include the main valve core of the main safety valve is stuck, the fit clearance between the valve rod and the valve body is too large, the pressure regulating spring is damaged, the seal in the valve is damaged or the valve body has sand holes. Disassemble and check whether the cone valve of the main safety valve is stuck. Check the fit clearance between valve rod and valve body. The normal fit clearance should be between 0.005 and 0.025mm, and the repair limit is 0.04mm. Check the fit clearance between the main valve core and the main valve sleeve. The normal fit standard clearance is 0.010~0.018mm, and the repair limit is 0.03mm. Check whether the pressure spring and valve inner seal are damaged.