Fault Phenomenon: Hitachi ZX200 excavator after swing stops, the upper structure automatically slides due to inertia or slope.

Troubleshooting Process:
– Checked brake: swing motor internal brake pads worn.
– Checked brake valve: brake release valve spool stuck in open position.
– Checked accumulator: brake accumulator pressure low.
– Checked spring: brake spring broken.

Root Cause: The friction pads of the normally closed brake inside the swing motor are excessively worn, resulting in insufficient braking torque.

Required Parts: Swing motor brake repair kit.