Fault Phenomenon: SANY SKT90 wide body mining truck when lifting the dump body, steering suddenly becomes heavy or loses steering ability.

Troubleshooting Process:
– Checked priority valve: flow priority valve spool stuck in work position.
– Checked spring: priority valve spring broken.
– Checked oil pressure: low steering system pressure.
– Checked pumps: work pump and steering pump internal leakage.

Root Cause: The flow priority valve spool is stuck due to debris; when the work system pressure rises, the spool fails to move to cut off work flow and ensure steering flow.

Required Parts: Clean or replace flow priority valve.