What’s the Common Inspection and Maintenance Methods for Hydraulic Piston Pumps

Brief Introduction of The Hydraulic Pumps

Hydraulic pumps, including hydraulic piston pumps, vane pumps, gear pumps, are widely applied to the construction machinery, industrial equipment, marine, and agricultural machinery.

The hydraulic piston pump fails to discharge hydraulic oil or the oil output is insufficient

If the hydraulic piston pump fails to discharge hydraulic oil or the oil output is insufficient, it maybe due to the following reasons:
• Suction port or oil pipe blockage:
Check whether the suction pipeline, filter, and oil tank are blocked by outside objects, and clean the pipes.
• Insufficient hydraulic oil or poor oil quality:
Check whether the oil level is sufficient and whether the oil is contaminated.
Replace the oil with clean oil if necessary.
• Pump body leakage:
Check whether the pump body’s gaskets are aged or damaged.
Replace the damaged gaskets and seals.
• Insufficient suction pressure:
Check whether the vacuum degree at the suction port is too high, and adjust the height of the suction port if necessary.

Excessive noise in the hydraulic piston pump

Excessive noise in the hydraulic piston pump will affect the normal operation of the equipment. The common reasons and solutions are as follows:
• Cavitation:
Due to low suction pressure, the hydraulic oil evaporates and forms bubbles. The bursting of these bubbles generates noise.
The solutions include increasing the suction pressure, ensuring the cleanliness of the hydraulic oil, or increasing the oil flow rate.
• Wear of internal components in the pump:
Check whether the components such as the pistons, cylinder block, and valve group inside the pump are severely worn. Replace the worn parts if any.
• Insufficient lubrication:
Check whether the lubricating oil is sufficient, whether there is any blockage, and whether the oil pump system is unobstructed.
Add appropriate lubricating oil to ensure proper lubrication.
• Pump installation issues:
Check whether the connection between the pump and the motor is correct, and whether the transmission part is loose or misaligned, that will makes the pump body vibrate.

Leakage in the hydraulic piston pump

Leakage in the hydraulic piston pump usually occurs at the seals, shaft seals, inlet and outlet joints, etc. The common reasons and solutions are as follows:
• Aging or damage of seals:
Check whether each seal of the pump is aged or damaged, especially at the piston seal, shaft seal, valve body seal, etc.
Replace the damaged seals in a timely manner.
• Improper installation:
Check whether the installation of the pump body and related connection parts meets the requirements, and whether the sealing surface is flat.
Improper installation can lead to leakage.
• Poor valve sealing:
If the control valve inside the hydraulic piston pump has poor sealing condition, it may lead to the internal oil leakage in the pump.
Check the valve seals and replace them if necessary.

Vibration of the hydraulic piston pump

The vibration problem of the hydraulic piston pump may stem from multiple aspects. The common reasons and solutions are as follows:
• Damaged bearings or insufficient lubrication:
Check whether the pump body bearings are damaged and whether the lubricating oil is sufficient. Replace the damaged bearings and add appropriate lubricating oil if there are any problems.
• Unbalanced or worn rotors:
Check whether the pump’s rotors and pistons are evenly worn.
Replace the worn parts or re-pair them if necessary.
• Connection problems between the pump and the motor:
Check whether the connection between the motor and the pump is correct and whether the alignment is appropriate.
Adjust the installation position if the connection is poor.

Unstable pump pressure

The unstable pressure of the hydraulic piston pump is usually manifested as large pressure fluctuations or unstable pressure output. The common reasons and solutions are as follows:
• Relief valve failure:
Malfunction of the relief valve will lead to the system pressure unregulated.
Check whether the relief valve is stuck and whether the spring is damaged.
Replace it if necessary.
• Problems with the hydraulic piston pump’s control system:
Check whether the control system (such as the speed control valve, load sensor, etc.) is working properly and whether the adjustment screws are loose.
• Hydraulic oil contamination:
Impurities in the oil may cause the internal valves or components of the hydraulic piston pump to jam, resulting in unstable pressure. Regularly check whether the hydraulic oil is clean and replace it if necessary.

Excessively high operating temperature of the pump

The excessively high operating temperature of the hydraulic piston pump may be caused by internal friction, excessive load, or oil problems. The solutions are as follows:
• Dirty hydraulic oil: Contaminants in the hydraulic oil may increase friction and lead to the temperature rise.
Check the quality of the hydraulic oil and replace it in a timely manner.
• Excessive pump load: Check whether the pump’s working load exceeds the rated load and avoid long-term overloading operation.
• Cooling system problems: Check whether the cooling system is working properly to ensure that the pump has sufficient heat dissipation.

Maintenance of the hydraulic piston pump

• Regular inspection: Regularly check the pump’s operating status, oil level, oil quality, and temperature to detect abnormalities in a timely manner.
• hydraulic oil replacement: Regularly replace the hydraulic oil to keep it clean.
• Filter cleaning: Regularly clean the filter to avoid difficult oil suction caused by blockage.
• Seal replacement: Regularly check the wear of the seals and replace them in a timely manner.