What should I do if my mini excavator bypass valve fails?

Small mini excavator bypass valve failure today to analyze the small excavator central bypass valve failure.

1. Boom lift, bucket low-speed digging and unloading, the central bypass valve is stuck in the open position, the oil output of the main pump to return to the hydraulic oil tank, the boom rise and bucket work circuit is not accessible, remove the central bypass line shaft for cleaning.

2. The movable arm rises slowly, and hydraulic noise occurs when the movable arm rises: the reason why the movable arm logic check valve is jammed, the pressure oil can not enter the movable arm lifting oil circuit, the movable arm logic check valve is removed.

3. The rocker extends or retracts at a low speed: the central bypass valve spool is stuck in the open position, the oil output from the main pump flows back to the hydraulic oil tank and cannot enter the working circuit of the bucket rod, the central bypass dismantles the valve for cleaning.

4. The motor starts to rotate, but the engine cannot start: the central bypass valve spool is stuck in the closed position, the oil output of pumps 1 and 2 cannot return to the hydraulic tank, the central bypass valve spool is disassembled for cleaning.