Fault Phenomenon: BelAZ 7530 mining truck when driving straight, the steering wheel does not return to center or the front end automatically drifts.

Troubleshooting Process:
– Checked steering cylinder: cylinder piston seals worn, internal leakage.
– Checked steering unit: full hydraulic steering unit internal leakage at neutral.
– Checked bi-directional cushion valve: cushion valve internal leakage.
– Checked mechanical connection: steering linkage loose.

Root Cause: The bi-directional cushion valve (anti-shock valve) inside the steering cylinder spool is stuck partially open due to debris, causing cross-communication between cylinder chambers.

Required Parts: Clean or replace steering cylinder cushion valve.