Small excavator bypass valve failure Today, let’s analyze the failure of the central bypass valve of a small excavator.
1. The boom is raised, the bucket is digging and unloading at a low speed, the central bypass valve is stuck in the open position, the oil output of the main pump returns to the hydraulic tank, the boom rises and the bucket working circuit is inaccessible, and the central bypass line shaft is removed for cleaning.
2. The boom rises slowly, and hydraulic noise occurs when the boom rises: the cause of the boom logic check valve being stuck, the pressure oil cannot enter the boom lifting oil circuit, and the boom logic check valve is removed.
3. The rocker extends or retracts at a low speed: the central bypass valve core is stuck in the open position, the oil output of the main pump flows back to the hydraulic tank, and cannot enter the bucket working circuit. The central bypass valve is disassembled for cleaning.
4. The motor starts to rotate, but the engine cannot start: the central bypass valve core is stuck in the closed position, the oil output of the main pumps 1 and 2 cannot return to the hydraulic tank, and the central bypass valve core is disassembled for cleaning.
