7 Common Hydraulic Pump Problems and How to Fix Them Fast

When your hydraulic pump fails, everything stops. That expensive excavator becomes a useless hunk of metal. The production line grinds to a halt. Your project deadline slips further away.

Hydraulic pump problems cost you time and money – but many can be fixed quickly if you know what to look for.

This guide cuts through the technical jargon to give you practical solutions for the most common hydraulic pump issues. We'll help you get your equipment running again fast, without unnecessary service calls.

7 Common Hydraulic Pump Problems and How to Fix Them

1. Unusual Noise (Cavitation)

That high-pitched whining or knocking sound from your hydraulic pump usually means cavitation – air bubbles forming and collapsing in the fluid.

Quick fixes:

• Check fluid levels first – low fluid is the most common cause

• Inspect the suction line for cracks or loose connections

• Clean or replace clogged suction filters

• Verify the fluid is the correct viscosity for your operating temperature

Pro tip: If you hear noise only during cold startup, your fluid might be too thick. Consider a fluid with better cold-flow properties.

2. Overheating

A hydraulic pump running hot (above 180°F/82°C) will quickly destroy itself.

Quick fixes:

• Check for proper fluid level – low fluid can't dissipate heat effectively

• Clean heat exchangers and cooling fins

• Reduce pressure settings if they exceed manufacturer specs

• Look for internal leakage (fluid bypassing where it shouldn't)

• Make sure your reservoir is properly sized (should be 3-5 times pump flow rate)

Pro tip: Touch the reservoir with your hand. If it's too hot to keep your hand on for 5 seconds, your system is running dangerously hot.

3. Not Building Pressure

When your pump runs but doesn't generate pressure, you can't do work.

Quick fixes:

• Check the pressure relief valve – it might be stuck open or set too low

• Look for obvious external leaks in lines and connections

• Test for internal pump wear with a flow meter

• Verify drive coupling is intact and properly connected

• Make sure the pump rotation direction matches the design

Pro tip: Mark your pressure gauge with acceptable minimum and maximum values so anyone can quickly spot a problem.

4. Erratic Movement of Cylinders

When hydraulic cylinders jerk, stutter, or move at inconsistent speeds, your precision work suffers.

Quick fixes:

• Bleed air from the system (air is compressible, hydraulic fluid isn't)

• Check for scored cylinder walls or damaged seals

• Clean or replace sticky control valves

• Look for restrictions in lines or filters

• Test for pump wear causing pressure fluctuations

Pro tip: If one cylinder works fine but another doesn't, the problem is likely in the cylinder or its control valve, not the pump.

5. Reduced Speed or Power

When your hydraulic equipment slows down or loses lifting power, productivity tanks.

Quick fixes:

• Check for slipping drive belts or couplings

• Look for partially blocked filters restricting flow

• Test relief valve settings – they may have drifted

• Inspect for worn pump components reducing displacement

• Make sure you're not exceeding the pump's rated capacity

Pro tip: Document normal operating pressures and speeds when equipment is new, so you can quickly identify when performance drops.

6. Fluid Leaks

External leaks waste fluid, create safety hazards, and signal potential system problems.

Quick fixes:

• Tighten loose fittings (but don't overtighten and damage threads)

• Replace damaged O-rings and gaskets

• Check for proper torque on flange bolts

• Look for cracked hoses, especially near fittings

• Replace worn shaft seals if leaking from the pump

Pro tip: Keep a kit of common O-rings, gaskets and seals for your equipment. Many leaks can be fixed in minutes if you have the parts on hand.

7. Contaminated Fluid

Dirty hydraulic fluid is the leading cause of system failures. Dark, cloudy, or foul-smelling fluid needs immediate attention.

Quick fixes:

• Change filters according to maintenance schedule or pressure indicators

• Replace fluid if it shows signs of contamination or degradation

• Inspect breather caps and make sure they're not clogged

• Check for water contamination (milky appearance)

• Look for potential contamination entry points like worn wiper seals

Pro tip: Hold a sample of your hydraulic fluid in a clear container up to the light. If you can't see through it, it's time for a change.

Essential Maintenance to Prevent Hydraulic Pump Failures

Prevention is always cheaper than repair. These simple maintenance steps take minutes but save thousands:

Daily Checks (2 minutes)

1. Look for leaks at the pump, hoses, and connections

2. Check fluid levels when the system is cold

3. Listen for unusual noises during operation

4. Feel for excessive heat on the reservoir and pump housing

Weekly Checks (5 minutes)

1. Inspect drive couplings for alignment and wear

2. Check filter indicators for clogging

3. Tighten any loose mountings that could cause vibration

4. Clean cooling fins if present

Monthly Checks (15 minutes)

1. Take a fluid sample to check for contamination

2. Record operating pressures to track performance trends

3. Check for line vibration that could cause fatigue failures

4. Verify relief valve operation and settings

Implementing just these simple checks will prevent most catastrophic pump failures and extend component life significantly.

How to Choose the Right Replacement Hydraulic Pump

When repair isn't an option, selecting the correct replacement pump is critical. Focus on these key factors:

1. Exact displacement (cubic inches per revolution) to match flow requirements

2. Pressure rating that meets or exceeds system demands

3. Mounting pattern and shaft configuration for direct replacement

4. Port sizes and locations to avoid custom plumbing

5. Control options that match your application needs

Don't just replace what you had – this is an opportunity to upgrade reliability or efficiency if your original pump was problematic.

Further reading: How to Choose the Right Hydraulic Pump Size

Conclusion: Keep Your Hydraulic Pumps Running Smoothly

Hydraulic pump problems don't have to mean expensive downtime and service calls. With these troubleshooting tips and maintenance practices, you can:

• Identify common issues quickly

• Fix many problems yourself with basic tools

• Prevent most failures before they happen

• Make smarter decisions about repair versus replacement

Clean fluid, proper installation, and regular maintenance are the keys to hydraulic pump reliability.

Address small issues before they become major failures, and your equipment will provide years of dependable service.

Chris Brown

Hi, I'm Chris Brown, a mechanical engineer who loves working with automotive tools. I've used many different tools, including wheel spacers, ball joint tools, helicoil kit, and other repair tools. I'm delighted to share simple tips, product reviews, and new technology in the automotive world. At Orion Motor Tech, I write to help everyone from hobbyists to expert mechanics, hoping that I can help you understand and use automotive tools better.