Hydraulic cylinders are important actuators in hydraulic systems, responsible for converting hydraulic energy into mechanical energy, and are widely used in various machinery and marine equipment. Due to their complex working environment and heavy loads, hydraulic cylinders may experience various faults during use. Understanding common faults and their repair methods is essential to improving the service life of the cylinder and the operating reliability of the system.
Common faults and repair methods

1. Cylinder oil leakage
Causes:
Aging or damage of seals
Scratches, corrosion or contamination on the piston rod surface
Poor sealing of the connection parts
Improper installation or cylinder overload
Repair methods:
Check seals: Check the various sealing parts of the cylinder, including piston seals, piston rod seals, end cover seals, etc. If there is wear or aging, replace new seals.
Clean the surface: Check the piston rod and other contact surfaces to ensure that the surface is smooth and scratch-free. If scratches are found, use sandpaper to smooth them or replace the damaged parts.
Check the installation: Make sure that the cylinder is installed in the correct position and the seals are installed in place. Avoid over-tightening the bolts or uneven installation.
Check the oil quality: Use suitable hydraulic oil and ensure that the oil is clean and free of impurities.

2. The cylinder piston is stuck or moves poorly
Reasons:
Internal contamination or high viscosity of hydraulic oil
Scratches or corrosion on the inner surface of the piston rod or cylinder
Damage to the piston seal, causing oil leakage
Blockage in the pipeline or valve
Repair method:
Check the oil: Check the viscosity and quality of the hydraulic oil, and confirm that the oil is not expired and free of impurities. Select the appropriate hydraulic oil according to the temperature conditions.
Clean the cylinder and piston rod: If there is foreign matter or dirt in the cylinder, the cylinder can be disassembled and the inner and outer surfaces can be cleaned to ensure that there are no particulate impurities.
Replace the seal: If the seal is damaged, resulting in poor piston movement, it needs to be replaced in time.
Check the pipeline and valve: Check whether the oil pipe and control valve are blocked or leaking, and clean or replace them if necessary.

3. The cylinder cannot return to its position
Reason:
The system pressure is too low or the hydraulic oil is insufficient
The return oil pipeline is blocked or the return oil speed is too slow
The internal seal of the cylinder is damaged
The hydraulic pump or valve is faulty
Repair method:
Check the oil: Check the oil level of the hydraulic oil to ensure that the hydraulic oil is sufficient. If the oil level is too low, add the hydraulic oil to the specified range.
Clean the return oil pipeline: Check whether there is blockage or oil leakage in the return oil pipeline, clean the pipeline or replace the damaged part.
Check the hydraulic system: Confirm whether the hydraulic pump is working properly and ensure that the system pressure is stable. If the hydraulic pump fails, it may need to be replaced or repaired.
Check the valve and control system: Confirm whether the valve is flexible, and adjust or replace it if necessary.

4. The cylinder noise is too loud
Reason:
There are bubbles in the hydraulic oil, causing air to enter the cylinder
There are impurities or wear inside the cylinder
The system pressure is too high or the oil viscosity is not suitable
The seal or valve is damaged
Repair method:
Vent: Exhaust air in the system to ensure that there are no bubbles in the hydraulic cylinder. When exhausting, you can operate through the exhaust port of the cylinder, or operate the hydraulic system when the oil is relatively clean.
Check the oil quality: Check the quality and viscosity of the hydraulic oil to ensure that the hydraulic oil meets the requirements. Use a filter to clean the oil to avoid impurities in the oil.
Check the system pressure: Ensure that the pressure of the hydraulic system meets the design requirements of the equipment. If the pressure is too high, adjust the pressure valve.
Check internal wear: Check whether the piston rod and cylinder of the cylinder have severe wear or scratches, and replace the damaged parts if necessary.

5. The cylinder cannot withstand the load or moves slowly
Causes:
The viscosity of the hydraulic oil is not suitable or the oil is deteriorated
Insufficient system oil pressure or valve failure
Internal wear of the cylinder or damage to the seal
Hydraulic pump efficiency decreases
Repair method:
Check the oil: Check the viscosity and quality of the oil to ensure that the oil meets the use requirements. If the oil is contaminated or deteriorated, it should be replaced in time.
Check the hydraulic system: Check the pressure of the hydraulic system to confirm whether the hydraulic pump provides sufficient flow and pressure. If the hydraulic pump efficiency decreases, it may need to be replaced or repaired.
Check valves and control systems: Check whether the system valves are stuck or faulty, ensure that the valves are flexible and the pressure control system is normal.
Check the inside of the cylinder: Check whether there is wear or damage inside the cylinder, replace the damaged parts in time, and restore the normal operation of the cylinder.

Conclusion
Common faults of hydraulic cylinders usually involve oil leakage, poor piston movement, inability to return to position, excessive noise, and slow movement. For different faults, first diagnose the cause of the fault, and then take appropriate maintenance measures, such as replacing seals, cleaning the oil, checking the inside of the cylinder, adjusting the system pressure, etc. During the maintenance process, pay attention to the standardization of operations, ensure the cleanliness of the hydraulic system and the quality of the oil, and avoid further failures due to contamination or unqualified oil. Regular maintenance and inspection of the hydraulic system can effectively increase the service life of the cylinder and ensure the safe operation of the hydraulic system.