Hydraulic Pressure Fluctuation? Key Excavator Main Pump Parts Selection Guide

Common Causes of Pressure Instability & Component Selection Advice

1. Excessive Wear on Cylinder Block and Pistons
Unstable pressure is often caused by internal wear. Replace worn-out cylinder block and piston groups (e.g., for REXROTH A8VO160), ensuring tight seal and consistent pressure delivery.

2. Aged Control Valve Seat or Piston
Erratic relief may stem from worn control pistons or seats. Select compatible parts to ensure accurate pressure modulation and quick response.

3. Clearance Issues in Center Pin & Retainer Plate
Improper fit between center pin and retainer plate can cause pressure surges. Use high-precision parts to improve stability under heavy-duty loads.

4. Clogged Relief Ports or Internal Leakage
Contamination or sealing failures in the relief path can result in pressure drop. Replace return filters, clean internal oil passages, and inspect all O-rings and seals.

5. Shaft and Gear Alignment Problems
A worn main shaft or gear misalignment can cause pressure fluctuation. Choose components with proper heat treatment and exact fit to original specifications.