Oil leakage in hydraulic cylinders is a common problem in hydraulic systems. Oil leakage not only leads to waste of hydraulic oil, but also may affect the working efficiency of the hydraulic system and the normal operation of the equipment. Understanding the causes of oil leakage in hydraulic cylinders and taking effective solutions is the key to maintaining the stable operation of the hydraulic system.

1. Causes of oil leakage in hydraulic cylinders
Damage or aging of seals
Causes: Seals are key components to prevent hydraulic oil leakage. Long-term use will cause aging, wear or cracking of seals, especially rubber seals are susceptible to damage under high temperature and high pressure environments.
Performance: Oil leakage generally occurs in the sealing parts of the cylinder such as the piston, piston rod, and end cover.

Improper installation of seals
Causes: If the seals are not installed in the correct way during installation, problems such as uneven compression, displacement, and damage may occur, resulting in poor sealing effect.
Performance: When the seals are improperly installed, oil leakage usually occurs at the beginning of installation.

The surface of the cylinder piston rod is worn or damaged
Reason: During the frequent extension and retraction process, the piston rod may rub against the inner wall of the cylinder, causing damage to the piston rod surface (such as scratches, dents, corrosion, etc.), thereby affecting the normal function of the seal and causing oil leakage.
Performance: The piston rod surface is obviously worn, scratched or rusted, and the seal ring cannot be effectively sealed, resulting in leakage.

Hydraulic oil pollution
Reason: Contaminants such as particles, impurities or moisture in the oil will accelerate the wear of the seal, damage the inner wall of the cylinder, and cause poor sealing, eventually causing oil leakage.
Performance: Water, impurities, sludge, etc. appear in the oil, and abnormal wear occurs on the surface of the cylinder and the seal ring.

The working pressure of the cylinder is too high
Reason: The hydraulic cylinder is designed with a certain working pressure range. If the working pressure exceeds its rated value, the seal may be deformed under pressure and leakage may occur.
Performance: When the cylinder is under high pressure, the seal will fail when it is under excessive pressure, resulting in oil leakage.

Excessive use of the cylinder or long-term high-load operation
Cause: The cylinder is in a state of high load and frequent use for a long time, which may cause excessive wear of internal and external parts, seal failure, and even deformation of the cylinder shell, causing leakage.
Performance: The equipment is used frequently, the seal fails seriously, and the oil leakage phenomenon gradually intensifies.

Poor assembly or deformation of the cylinder
Cause: If the sizes of the various components do not match during the assembly of the cylinder, or the cylinder housing, piston rod, etc. are deformed, it may affect the sealing performance and cause oil leakage.
Performance: Oil leakage caused by assembly error or cylinder deformation is usually serious, and the leakage point is irregular.

Seal deformation caused by temperature change
Cause: The increase in oil temperature in the hydraulic system may cause the seal to soften or deform, and the low temperature may cause the sealing material to become brittle. This change will affect the effect of the seal and cause oil leakage.
Performance: In a high temperature environment, the cylinder seal ages and softens, resulting in poor sealing; in a low temperature environment, the seal becomes brittle and cracked.

2. Solutions to oil leakage in hydraulic cylinders
Replace damaged seals
Solution: When seals are aged, worn or cracked, they need to be replaced in time. When replacing seals, make sure to use sealing materials that match the original model, such as fluororubber, polyurethane, etc., to adapt to the type of hydraulic oil and working environment.
Precautions: When replacing seals, ensure cleaning to avoid contamination of new seals and affect their normal use.

Correctly install seals
Solution: Check whether the seal is installed in the correct position. When installing the seal, ensure that there is no deviation or damage to the seal, and ensure that its installation direction, compression degree, etc. meet the requirements.
Precautions: Before installation, check whether the seal is damaged or defective, and avoid scratching or damaging the seal during installation.

Repair or replace worn piston rods
Solution: If the surface of the piston rod is severely worn, it can be repaired, such as polishing, grinding, or chrome plating, to restore its smoothness and wear resistance. If the piston rod is severely damaged, it needs to be replaced.
Precautions: During the repair of the piston rod, ensure that its surface is flat and smooth to avoid damage to the new seal.

Clean the oil and replace the filter
Solution: Check the cleanliness of the hydraulic oil regularly, clean or replace impurities in the oil in time, prevent contaminants from entering the cylinder and affecting the performance of the seal and cylinder. Use a suitable filter to prevent oil contamination.
Note: To ensure that the cleanliness of the oil meets the requirements of the hydraulic system, you can use filters and oil analyzers for regular monitoring and replacement.

Adjust the working pressure to the rated range
Solution: Check the pressure control valve in the hydraulic system to ensure that it works within the rated pressure range of the hydraulic cylinder. Avoid seal failure caused by overpressure.
Note: Check the system pressure regularly to ensure that all parameters meet the design requirements and avoid the cylinder running under high pressure.

Reduce the load and operation frequency of the cylinder
Solution: Reasonably arrange the use cycle of the equipment to avoid the cylinder being in a high load or frequent start-stop state for a long time. Reduce the impact and wear on the cylinder through appropriate working condition adjustment.
Note: Keep the load of the hydraulic system within the design range and reduce the burden on the cylinder to extend the service life of the cylinder.

Check and repair assembly problems
Solution: Check the assembly quality of the cylinder and its components to ensure that there is no deformation, looseness or improper installation of the internal and external components of the cylinder. If deformation or assembly error is found, the components need to be replaced or repaired.
Note: Ensure process accuracy during assembly to avoid leakage caused by assembly problems.

Control the impact of temperature changes on the cylinder
Solution: To avoid the impact of temperature changes on seals, you can install oil temperature monitoring devices and cooling systems to control the oil temperature and keep it within an appropriate range.
Note: Check the oil temperature regularly to keep the temperature of the hydraulic oil stable and avoid aging or embrittlement of the seals caused by too high or too low temperatures.

3. Summary
Hydraulic cylinder oil leakage is a common but preventable and solvable problem. By regularly checking seals, replacing damaged parts, cleaning oil, adjusting working pressure and other measures, the oil leakage problem can be effectively solved and the stability and safety of the hydraulic system can be improved. In actual work, timely detection and resolution of oil leakage problems can not only extend the service life of the cylinder, but also improve the working efficiency of the hydraulic system and reduce maintenance costs.