Applicable Systems
EC220 Excavator
Symptoms
Lift and tilt functions become sluggish; hydraulic pump noisy.
Possible Causes
- Hydraulic pump cavitation due to clogged suction strainer.
- Pump shaft splines worn causing slip between engine and pump.
- Hydraulic oil viscosity too high for cold ambient temperature.
Troubleshooting Steps
- Step 1: Remove suction strainer and inspect for debris.
Strainer clean; no rags or hardened O-ring fragments. - Step 2: Inspect pump drive coupling and shaft splines.
Splines intact; no rounding or backlash > 2°. - Step 3: Check oil viscosity grade vs ambient temperature chart.
Oil grade ISO VG 46 for -10°C to +40°C ambient.
How to Reset
Clean or replace suction strainer; replace pump drive coupling; change to correct oil grade.
Common Replacement Parts
- Suction Strainer 11713258: Suction Strainer 11713258
- Pump Drive Coupling 11717493: Pump Drive Coupling 11717493
Frequently Asked Questions
- Q: Can I use ISO VG 68 in summer?
Yes if ambient > 30°C, but avoid mixing grades without full drain.
- Q: What noise indicates cavitation?
High-pitched whine or rattle, worse at high RPM.
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Source: Volvo L120H Hydraulic Manual
Category: Heavy Equipment
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