Don't Wait for a Complete Failure
A hydraulic pump replacement costs anywhere from $2,000 to $8,000+ depending on the machine. Catching a failing pump early — before it destroys downstream components like control valves and cylinders with metal contamination — can mean the difference between a planned shop repair and an emergency rebuild.
1. Slow Cycle Times
If your boom, stick, or bucket are noticeably slower than they used to be, and the problem cannot be attributed to a control valve issue, internal pump wear is the most likely cause. As pistons and barrel wear, volumetric efficiency drops — the pump moves less fluid per revolution. Use a flow meter if possible: a new pump should deliver within 5% of rated flow; more than 15% loss typically justifies replacement.
2. High System Temperature
A worn pump generates more heat than it should because internal bypass — fluid leaking from high pressure back to the case — converts hydraulic energy into heat instead of work. If your machine is running hot without an obvious external cause (blocked cooler, low fluid level), suspect internal pump bypass.
3. Whining or Moaning Noises
A hydraulic pump should be relatively quiet at operating temperature. A high-pitched whine usually indicates cavitation — the pump is being starved for fluid, often due to a clogged suction strainer or a failing charge pump. A low moaning sound under load is more often internal wear. Either way, investigate immediately.
4. Metal Particles in the Hydraulic Filter
If your return filter is capturing small, bright metal particles (cut the filter element open and inspect it), you have internal wear generating debris. This is an urgent warning — those particles are circulating through your entire system and scoring every precision-machined surface they contact. Change the fluid, replace the filter, and get the pump rebuilt or replaced before the debris causes a cascade failure.
5. Erratic or Jerky Machine Movements
Intermittent loss of pressure due to a sticking or worn pump regulator or worn internal seals can cause unpredictable, jerky boom and stick movements. This is both a productivity problem and a safety issue — an excavator that does not respond predictably is a hazard on a job site.
If your machine is showing any of these symptoms, call us. We can help you diagnose whether you are looking at a pump, control valve, or another hydraulic issue, and we stock rebuilt pumps for most major excavator models ready to ship.