1. Failure phenomenon
Due to the failure of the pilot control valve, main operation valve spool, anti-slip valve, overload supplement valve, hydraulic cylinder oil seal, etc., the boom, stick and bucket hydraulic cylinder slip.
2, fault diagnosis and troubleshooting steps
(1) Check whether the slip of each hydraulic cylinder is within the specified range (the slip of the boom, stick and bucket hydraulic cylinder is less than 20mm/5min), if it is within this range, the hydraulic cylinder is normal
(2) If the slip of the hydraulic cylinder exceeds the specified range, first close the pilot shutoff valve and check whether the slip of the hydraulic cylinder is reduced. If the amount of slippage decreases, it means that the pilot control valve is malfunctioning; if the amount of slippage does not decrease and continues to increase, check the boom slide valve in the four-way reversing valve and the five-way reversing valve in the main operating valve. Whether the inner stick slide valve is adjusted correctly. If it is not adjusted well, readjust it and lock it.
(3) If the anti-slip valve is adjusted correctly, but the hydraulic cylinder still continues to slip, you should temporarily change the overload charge valve in the oil circuit of other hydraulic cylinders to check whether it is still slipping. If it does not slip, then explain The overload charge valve is faulty; if it continues to move, check whether the hydraulic cylinder has internal leakage
(4) If the hydraulic cylinder leaks internally, replace the hydraulic cylinder seal; if the hydraulic cylinder does not leak internally, it means that the main operating spool is scratched, the spring is damaged, or the end of the spool is loose.
