Flange Mounted Rexroth Plunger Pump A4VSO71EO1/10R-PZB13N00 A4VSO71EO1/10R-VPB13N00 A4VSO71EO1/10R-PPB13N00

A1: Pressure insufficiency is a frequent issue -- diagnose in this order:

1. Control System Check:
   • For LR2 mode: Verify the power feedback sensor signal (4-20mA). A loose connection or damaged sensor will cause the pump to operate at minimum displacement.
   • Check the control port X pilot pressure (required 30-40 bar). Low pilot pressure (≤20 bar) prevents the swashplate from reaching maximum angle. Adjust the pilot relief valve to restore pressure.
2. Hydraulic Circuit Inspection:
   • Test the main relief valve: If it is stuck open (due to contamination), it will bleed pressure continuously. Disassemble and clean the valve core with diesel; replace if the valve seat is scratched.
   • Check for external leaks: A 1 mm crack in the pressure hose can reduce system pressure by 50 bar. Use a leak detector or soap solution to identify leaks.
3. Internal Component Wear Check:
   • Disassemble the pump and measure piston-cylinder clearance (normal ≤0.02 mm). If clearance exceeds 0.03 mm, replace the piston-cylinder pair (Rexroth part number R900909645).
   • Inspect the valve plate and cylinder block contact surface: If there are scratches ≥0.01 mm deep, lap the surfaces with 600-grit abrasive paper until the contact area reaches ≥90%.