Bobcat mini excavator boom leaks down after cylinders were rebuilt: what next?
Short Answer
If the boom still leaks down after the cylinders were rebuilt, do not keep ordering cylinder seal kits without isolating the circuit. The next checks are the boom holding valve, control valve spool leakage, port relief valve, hose routing, and whether the rebuilt cylinders were tested for internal bypass.
What To Check
- Confirm whether the boom drops only with the engine off, only when warm, or also while other functions are being used.
- Test cylinder bypass separately from the boom holding valve and main control valve before buying more parts.
- Send the machine model, serial number, cylinder photos, valve-block photos, and previous rebuild details for parts matching.
Related JIAJUE Parts
Send the machine model, serial number, old part label, and clear photos 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 excavator hydraulic cylinder drifts down seal kit forum. The answer is rewritten from JIAJUE parts-matching and sourcing practice, not copied from the source page.
