Introduction
If your excavator is losing power, making unusual noises, or responding slowly to hydraulic controls, it may be time to replace the main hydraulic pump. This component plays a critical role in delivering pressure to the entire system — and when it fails, your machine’s performance suffers.
In this guide, we’ll walk you through how to safely and effectively install a new main pump on an excavator, such as a CAT 320C, Komatsu PC200, or other common models.
Tools and Materials You Will Need
– Compatible main pump (OEM or high-quality aftermarket)
– Torque wrench and basic hand tools
– Hydraulic hose plugs
– New hydraulic fluid (as per machine spec)
– Safety gloves and goggles
– Clean rags and thread sealant
Step-by-Step Replacement Instructions
Step 1: Shut Down Safely
– Park the excavator on a level surface.
– Turn off the engine and remove the key.
– Disconnect the battery.
– Relieve pressure from the hydraulic system via the bleed valve.
Step 2: Drain Hydraulic Oil
– Open the return line or drain plug.
– Collect oil in a clean container (dispose or filter as needed).
– Remove the filters if heavily contaminated.
Step 3: Disconnect the Pump
– Label and disconnect all hydraulic hoses and connectors.
– Remove any electrical connectors carefully.
– Loosen and remove the pump’s mounting bolts using proper torque tools.
Step 4: Clean the Mounting Area
– Remove debris and oil residues from the mounting plate and shaft.
– Check for wear or misalignment in the drive gear or couplings.
Step 5: Prepare the New Pump
– Confirm it matches your machine’s specs.
– Rotate the shaft manually to ensure it’s not jammed.
– Apply a small amount of hydraulic oil to the shaft and mounting face.
Step 6: Install the Pump
– Carefully position and align the pump.
– Tighten the bolts in a crisscross pattern to the specified torque.
– Reconnect all hydraulic lines and electrical connectors.
Step 7: Refill and Test
– Fill the tank with clean hydraulic fluid.
– Start the engine at idle and observe system pressure.
– Bleed the system and watch for leaks or abnormal noises.
– After 30 minutes, recheck fluid levels and fitting torque.
Common Mistakes to Avoid
| Mistake | Consequence |
|——–|————-|
| Using incorrect pump model | Poor flow rate, compatibility issues |
| Not bleeding air from the system | Cavitation, overheating |
| Reusing contaminated oil | Pump damage, clogged valves |
| Over-torquing bolts | Flange warping, seal failure |
When to Replace the Main Pump
– Weak hydraulic action even after filter change
– Noisy or whining pump under load
– Oil overheating despite correct fluid
– Visible internal leakage or worn shaft seals
A typical main pump has a service life of 6,000–8,000 hours. Timely replacement avoids expensive downtime and further damage.
Where to Source a Reliable Replacement
When replacing such a critical component, quality matters. Whether you use genuine OEM or aftermarket parts, make sure they come from a reputable source.
KERRYPARTS is a trusted supplier of high-quality excavator parts, including hydraulic pumps compatible with CAT, Komatsu, Hitachi, and Volvo machines. Our parts are matched to OEM specifications and backed by expert support for installation and compatibility.
Learn more or request a quote at www.kerryparts.com
Final Tips
– Always reference your excavator’s service manual before beginning any repair
– If in doubt, consult a certified technician — especially for high-pressure systems
– Log all replacements and usage hours for future maintenance scheduling
FAQ
Q: How do I know if my excavator’s main pump is failing?
A: Signs include loss of power, slow hydraulic response, noise during operation, or overheating oil.
Q: Can I replace a main pump myself?
A: Yes, if you have mechanical experience and follow safety procedures. Otherwise, consult a technician.
Q: How much does an excavator main pump cost?
A: Prices vary from $600 to $2,000+ depending on brand and model. KERRYPARTS offers competitive options.