Applicable Systems
CX210 Excavator
Symptoms
Slew (swing) stops intermittently; resumes after lever re-center.
Possible Causes
- Slew pilot valve spool return spring broken.
- Slew motor brake release pressure insufficient.
- Slew relief valve popping open due to load spikes.
Troubleshooting Steps
- Step 1: Remove slew pilot valve and inspect return spring.
Spring intact; free length 35 mm per spec. - Step 2: Measure brake release pressure at motor test port.
Release pressure 2.5–3.0 MPa when slew lever activated. - Step 3: Check slew relief valve setting and seat condition.
Relief set 27.5 MPa; seat clean, no wire-drawing marks.
How to Reset
Replace pilot valve spring or slew motor brake seals; replace relief valve if seat damaged.
Common Replacement Parts
- Pilot Valve Spring 1542923C1: Pilot Valve Spring 1542923C1
- Slew Motor Seal Kit 1542924C1: Slew Motor Seal Kit 1542924C1
Frequently Asked Questions
- Q: Is intermittent slew safe?
No, unpredictable swing can strike workers or structures.
- Q: What causes relief valve seat damage?
Pressure spikes from sudden load changes or contaminated oil.
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Source: Case CX210 Hydraulic Manual
Category: Heavy Equipment
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