An excavator hydraulic problem usually points to one of four areas: fluid, filtration, pump, or a valve/cylinder fault. Run through these in order before you tear anything apart.
1. Check fluid level and condition
Cold? Milky? Smells burnt? You've got a contamination problem before you have a hydraulic problem.
2. Check filter indicators
Clogged suction or return filters cause everything from sluggish action to pump cavitation.
3. Listen at the pump
Whine on a cold start is cavitation. Knock under load is air or wear. Either way, stop running it until diagnosed.
4. Test pressures
Hook a gauge to the test port and check main system pressure, then function pressures. Compare to OEM spec. Low pressure usually points to relief valve or pump issues.
5. Diagnose by symptom
- Sluggish boom or arm: low pressure, contaminated fluid, worn pump, internal cylinder leak.
- Cylinder drift: internal cylinder bypass (seal failure) or valve bypass.
- Overheating: internal bypass somewhere, low fluid, bad cooler, or wrong fluid viscosity.
- Erratic motion: air in the system or valve spool wear.
6. When in doubt, call
Misdiagnosed cylinder swaps and pump replacements are expensive. If you're not sure, send us a phone video — we'll often diagnose it before we drive out.