Applicable Systems
PC200 Excavator
Symptoms
Boom and arm motions slow simultaneously; hydraulic oil temperature high.
Possible Causes
- Main hydraulic pump swashplate angle reduced due to servo piston wear.
- Hydraulic oil cooler bypass valve stuck open.
- Return filter partially clogged raising back pressure.
Troubleshooting Steps
- Step 1: Measure pump delivery flow at rated engine speed.
Flow ≥ 2 × 224 L/min for tandem pump at 2000 RPM. - Step 2: Check oil cooler inlet vs outlet temperature.
Temperature drop across cooler ≥ 10°C at full load. - Step 3: Replace return filter and note pressure drop before/after.
Back pressure drops by > 0.15 MPa after filter change.
How to Reset
Overhaul main pump; replace cooler bypass valve; replace return filter.
Common Replacement Parts
- Main Pump Assembly 708-2L-00600: Main Pump Assembly 708-2L-00600
- Return Filter 207-60-61250: Return Filter 207-60-61250
Frequently Asked Questions
- Q: What causes pump swashplate wear?
Contaminated oil or prolonged operation at relief pressure.
- Q: Can I clean and reuse hydraulic filter?
No, Komatsu filters are non-cleanable; replacement only.
Source: Komatsu PC200-8 Hydraulic Shop Manual
Category: Heavy Equipment