Need to Pinpoint Hydraulic System Issues? Follow This Troubleshooting Checklist

Hydraulic system failures don’t come out of the blue. They often come after common symptoms, such as a gradual or sudden loss of pressure, arise.

Where to Start the Process

Step 1: Inspect Fluid and Pump Suction Strainer

• Increased pump noise
• Loss of pressure and/or speed
• Loss of flow

• Check fluid levels: Ensure that the hydraulic reservoir is properly filled. Low fluid levels can cause cavitation, leading to air being drawn into the pump.
• Examine fluid quality: The fluid should be clean, clear, and free from contaminants. Dark, milky, or foamy fluid indicates oxidation, air entrapment, or water contamination.
• Inspect the pump suction strainer: The suction strainer is located at the pump’s inlet to prevent debris from entering and damaging the pump. If the strainer is clogged, it can starve the pump of fluid, causing cavitation and reduced performance. Remove the suction strainer and inspect it for blockages. Clean or replace it if necessary. Ensure that no contaminants are reintroduced when reinstalling.
• Look for leaks: Visually inspect the pump, hoses, and fittings for any signs of leakage. External leaks may point to damaged seals, cracked hoses, or loose connections.

Step 2: Pump and Relief Valve Testing

• Check for unusual noises: Loud whining or knocking noises are often the result of cavitation or air being drawn into the system due to a clogged suction strainer or low fluid levels.
• Monitor system pressure: Use a pressure gauge to ensure the pump is delivering proper pressure. Low pressure output may indicate internal wear, incorrect settings, or issues with fluid flow.
• Feel for overheating: Overheating often results from internal friction due to fluid contamination, misalignment, or insufficient lubrication. Addressing these issues promptly can prevent pump failure.

Next, consider these four common pump problems and their solutions:

1. Pump is not delivering pressure

• Possible causes: Worn pump components, clogged pump suction strainer, or incorrect pressure settings.
• Solution: Clean or replace the suction strainer if clogged, inspect internal pump components for wear, and verify the settings on the pressure relief valve.

2. Pump cavitation

• Possible causes: Low fluid levels, a blocked suction strainer, or restricted inlet lines.
• Solution: Ensure fluid levels are correct, clean the suction strainer, and inspect the inlet line for any restrictions or collapsed hoses.

3. Pump overheating

• Possible causes: Contaminated fluid, insufficient cooling, or over-pressurization.
• Solution: Change or filter the hydraulic fluid, inspect the system’s cooling mechanisms, and verify that pressures are within pump specifications.

4. Noisy pump operation

• Possible causes: Air in the system or worn internal parts.
• Solution: Check for loose fittings or damaged seals that may be introducing air into the system and replace any worn internal components.

Step 3: Internal Pump Inspections and Reassembly

• Inspect the pump suction strainer: If you haven’t already, inspect the strainer again for any accumulated debris or blockages.
• Check rotors and bearings: Look for signs of wear or scoring that could reduce the pump’s ability to generate pressure efficiently.
• Inspect seals: Damaged seals can allow fluid leaks or air to enter the system, affecting pump performance. Replace worn seals and O-rings as needed.

• Recheck pressure output: Ensure the pump is delivering proper pressure, and use a pressure gauge to monitor its performance.
• Listen for abnormal noises: If unusual noises persist, there may still be air trapped in the system, or additional parts may need attention.
• Verify fluid cleanliness: Make sure the fluid remains clean and at the proper level after reassembly to ensure smooth operation.

Figure 1: Problem areas to inspect while troubleshooting