Oil leakage from hydraulic cylinders is one of the common problems in hydraulic systems. Oil leakage not only leads to reduced efficiency of the hydraulic system, but also may cause environmental pollution, safety hazards in the workplace, and equipment damage. Therefore, once the marine cylinder manufacturer finds that the hydraulic cylinder is leaking, it should promptly identify the cause and take effective repair measures. The following are common causes, diagnostic methods, and corresponding solutions for hydraulic cylinder oil leakage.

Common causes of hydraulic cylinder oil leakage
Damage or aging of seals
Seals are key components of hydraulic cylinders to prevent hydraulic oil leakage. With the increase of use time, seals may age, wear, harden, crack or deform, resulting in poor sealing, which in turn causes oil leakage.
Damage or scratches on the surface of the cylinder
If there are scratches, pits or excessive wear on the piston rod and cylinder body of the cylinder, it will affect the normal operation of the seal and cause oil leakage.
Improper installation or loose joints
When installing hydraulic cylinders, if the engineering cylinder manufacturer is not properly aligned or the fasteners are not tightened, it may cause the joints to loosen, resulting in oil leakage.
Too high pressure in the hydraulic system
The pressure in the hydraulic system exceeds the design range of the hydraulic cylinder, which will increase the burden inside the cylinder, causing the seal to be unable to withstand high pressure and cause leakage.
Hydraulic oil contamination
If there are impurities or moisture in the hydraulic oil, it may cause damage to the seal, or increase friction, causing increased wear of the cylinder and oil leakage.
Temperature is too high or too low
When the hydraulic system is working, high or low temperature will affect the viscosity of the hydraulic oil, which may cause the sealing performance to decrease or the cylinder parts to expand, increasing the risk of oil leakage.

Diagnostic methods for hydraulic cylinder oil leakage
Check the oil leakage site
Observe all parts of the hydraulic cylinder, especially around the seal, the contact between the piston rod and the cylinder body, and each joint. Oil leakage usually occurs in these areas.
Clean the surface of the cylinder
Apply a clean cloth or paper towel to the oil leakage site to remove excess oil stains and avoid contamination. Then run the hydraulic system to check the extension position of the oil stain, which will help locate the source of the oil leakage.
Pressure test
Use a pressure gauge to test the pressure of the hydraulic system and check whether it exceeds the design range. If the pressure is too high, it may cause damage or deformation of the seal.
Check the quality of the hydraulic oil
Check whether the hydraulic oil is clean and check whether it contains impurities or moisture. If the hydraulic oil is of poor quality, it should be replaced immediately.
Check the temperature
Check the temperature of the hydraulic oil to ensure that it is within the operating temperature range. Too high or too low temperature may affect the sealing performance.
Solution to hydraulic cylinder oil leakage

Replace damaged or aging seals
Regularly checking and replacing the seals of hydraulic cylinders is an effective way to prevent oil leakage. Choose the appropriate seal material according to the type of cylinder and the working environment. The steps for replacing seals usually include:
Turn off the power and pressure source of the hydraulic system.
Disassemble the cylinder and clean the cylinder barrel, piston rod and other parts.
Replace the seal and make sure the new seal is installed in place and is not damaged.
Reassemble and check the operation of the cylinder to ensure that there is no oil leakage.
Repair damage to the cylinder surface
If there are scratches or damage on the surface of the piston rod or cylinder barrel, you can use professional repair tools to polish the surface or replace the damaged parts. For severely damaged cylinders, the entire cylinder may need to be replaced.
Inspect and adjust the installation
Make sure that the hydraulic cylinder is installed in the correct position and all fasteners (such as bolts, flanges, joints, etc.) are tightened in place. Check the centering of the cylinder to ensure that there is no distortion or imbalance during installation.
Reduce the pressure of the hydraulic system
If the pressure of the hydraulic system is too high, you can reduce the system pressure by adjusting the pressure valve to ensure that the pressure is within the working range of the hydraulic cylinder to avoid oil leakage caused by excessive pressure.
Replace the hydraulic oil
If the hydraulic oil is contaminated, it must be replaced immediately. Check the cleanliness of the hydraulic oil regularly and take measures to prevent moisture or impurities from entering the oil. It is recommended to filter and replace the hydraulic oil regularly.
Improve the cooling effect of the hydraulic system
If the hydraulic oil temperature is too high, check whether the cooling system of the hydraulic system (such as radiator, coolant, etc.) is working properly. Make sure the radiator is clean and the coolant flow is sufficient to avoid seal failure due to excessive temperature.
Use appropriate temperature control devices
In working environments with large temperature changes, consider installing temperature control devices (such as oil temperature sensors, coolers, etc.) to ensure that the hydraulic oil remains within the normal temperature range.

Measures to prevent hydraulic cylinder oil leakage
Regularly check and replace seals: Check the seals of the hydraulic cylinder in time and replace them regularly as needed. Avoid oil leakage caused by aging or damage of seals.
Maintain the cleanliness of the hydraulic oil: Check the quality of the hydraulic oil regularly, keep the oil clean, and prevent contaminants and moisture from entering the system. Use an appropriate filtration system to clean the oil.
Keep the hydraulic system pressure stable: Use a suitable pressure valve and check the system pressure regularly to avoid damage to the hydraulic cylinder due to excessive pressure or fluctuations.
Install temperature control equipment: When working in a high temperature environment, install a hydraulic oil cooler or cooling system to avoid seal failure caused by excessive oil temperature.
Pay attention to installation and operation: Ensure that the cylinder is in the correct position during installation and the fasteners are tightened in place to avoid overload or incorrect operation during operation.

Summary
Hydraulic cylinder oil leakage is one of the common faults in hydraulic systems. Timely diagnosis and resolution of oil leakage problems are essential for the normal operation and production efficiency of equipment. Through regular inspections, timely replacement of seals, ensuring the quality of hydraulic oil, and adjusting system pressure, the problem of hydraulic cylinder oil leakage can be effectively prevented and resolved. Maintain the stability and cleanliness of the hydraulic system to ensure that the hydraulic cylinder works reliably for a long time and avoid oil leakage.