Fault Phenomenon: XCMG XKT mining truck all work equipment actions are weak, unable to lift heavy loads.

Troubleshooting Process:
– Checked relief valve: main relief valve spool stuck in open position.
– Checked spring: pressure regulating spring broken.
– Checked oil quality: contaminated fluid causing spool sticking.
– Checked pressure: system pressure measured extremely low.

Root Cause: The main relief valve on the multi-way valve group is stuck in the normally open position due to debris, causing system pressure to dump directly back to the tank.

Required Parts: Clean or replace main relief valve spool and spring.