Hydraulic Main Piston Pump 391-9442 for E312D2 313D Excavator

This hydraulic main piston pump is the core power component of the excavator hydraulic system, compatible with the E312D2 and 313D models. It supplies pressure oil for boom, arm, bucket, and travel movements. Manufactured with precise processing, it delivers stable output pressure and excellent wear resistance, making it an ideal choice for machine overhaul and replacement.

The following symptoms typically indicate that the hydraulic main piston pump requires inspection or replacement:

• Weak digging force and slow working speed
• Abnormal noise and vibration during operation
• Internal wear leading to pressure drop
• Oil leakage at the pump assembly sealing surface
• Unstable hydraulic flow and action jitter

To ensure correct fitment and reliable performance, please observe the following before ordering and during installation:

• Verify the machine model before placing your order
• Confirm the part number matches your old pump
• Keep hydraulic oil clean during installation
• Replace the sealing kit together if necessary