Excavator loses hydraulic speed when using multiple functions: pump, relief, or valve?
Short Answer
When single functions seem acceptable but combined functions slow down badly, suspect pump flow, pump control, load-sensing signal, relief bypass, or internal leakage. A pressure-only test may not catch the issue; flow testing and function comparison are usually needed.
What To Check
- Compare single-function speed with combined-function speed at the same engine rpm.
- Check pump flow, LS or regulator signal, main relief pressure, and hot oil temperature.
- Confirm whether the problem affects travel, boom, arm, bucket, and swing equally or only one circuit group.
Related JIAJUE Parts
Send the machine model, serial number, failed-part photos, measurements, and old part labels before ordering so JIAJUE PARTS can help reduce wrong-fitment risk.
Source Record
This question was selected from a current Google-visible result for the keyword Case 9020 hydraulic pump multiple functions slow. The answer is rewritten from JIAJUE parts-matching and sourcing practice, not copied from the source page.
