Fault Phenomenon: XCMG LW500 wheel loader boom lift speed is normal when operated alone, but weak under heavy load or combined operation.

Troubleshooting Process:
– Checked main pump: work pump severe internal leakage.
– Checked multi-way valve: main relief valve set too low or stuck.
– Checked cylinder: boom cylinder internal leakage.
– Checked pilot pressure: insufficient pilot control pressure.

Root Cause: The main relief valve spool in the multi-way valve is stuck partially open by debris, preventing system pressure from reaching the rated value.

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