Why does the hydraulic cylinder still leak oil after replacing the seal?

As a key actuator in the hydraulic system, the stability of the hydraulic cylinder directly affects the operating efficiency of the mechanical equipment. However, after long-term use, oil leakage in the hydraulic cylinder is a common problem, which is usually solved by replacing the seal ring. But sometimes, even if a new seal ring is replaced, the oil leakage problem cannot be completely eliminated. The following will analyze the possible causes and propose corresponding solutions.

1.Sealing Ring Installation Problem

Correct installation of the seal is the key to ensuring the sealing effect. If the standard operating procedures are not followed when replacing the seal, the seal may not be able to effectively contact the surface of the hydraulic cylinder, resulting in oil leakage. Common installation problems include incorrect seal direction, unclean seal grooves, uneven installation, etc.

These problems will lead to poor sealing, thus affecting the normal operation of the hydraulic system. The key to solving this problem is to ensure that the seal is installed correctly and the seal groove is thoroughly cleaned to avoid any interference from foreign matter or oil.

2.Seal Quality or Size Is Not Suitable

The quality of the seal ring is an important factor in preventing oil leakage. If the seal ring material is unqualified, or its temperature and pressure resistance do not meet the working environment requirements of the hydraulic cylinder, the seal ring will not be able to play its due sealing role even if it is installed correctly. Similarly, if the replaced seal ring size is not appropriate (too large or too small), it will also lead to unsatisfactory sealing effect.

To solve this problem, it is necessary to select sealing rings with strong adaptability and guaranteed quality, and ensure that their materials and specifications fully match the design requirements and working conditions of the hydraulic cylinder.

3.Hydraulic Cylinder Surface Damage

Damage to the piston rod and cylinder surface of the hydraulic cylinder is one of the common causes of oil leakage. If there are scratches, pits, rust and other problems on the surface of the hydraulic cylinder, the seal ring cannot form a perfect sealing contact with it, resulting in oil leakage. Surface damage may be caused by long-term friction, environmental dust pollution or impurities in the oil.

To solve this problem, the surface of the hydraulic cylinder needs to be comprehensively inspected and polished or ground if necessary to restore its smoothness to ensure good contact between the sealing ring and the surface of the hydraulic cylinder.

4.Hydraulic System Pressure is Too High

If the working pressure of the hydraulic system exceeds the tolerance of the hydraulic cylinder and the seal ring, it will also cause oil leakage. If the system pressure is too high, it will cause the seal ring to deform, crack or age, thus affecting its sealing performance. Therefore, it is very important to check whether the working pressure of the hydraulic system meets the design specifications of the hydraulic cylinder. If the pressure is found to be excessive, the pressure control device should be adjusted in time to ensure that the system operates within the specified range to avoid oil leakage caused by excessive pressure.

5.Work Environment Factors

The working environment of the hydraulic cylinder, such as changes in temperature and media, may also have an impact on the performance of the seal. In an environment with high temperature or corrosive media, the seal may swell or age, thus losing its sealing effect. Similarly, a low temperature environment may also cause the seal to harden, reducing its elasticity and sealing ability.

Therefore, when selecting a sealing ring, the working environment should be comprehensively considered, and sealing rings with high temperature resistance, corrosion resistance and other characteristics should be selected to ensure that they can maintain good sealing performance in various environments.

6.Effect of Hydraulic Oil

The quality and cleanliness of hydraulic oil have a direct impact on the service life of the seal ring. Impurities, sediments or moisture in the hydraulic oil may cause wear to the seal ring, resulting in reduced sealing effect. If the hydraulic oil is contaminated for a long time or does not meet the requirements of the hydraulic cylinder, even if the seal ring is replaced, the oil leakage problem cannot be effectively solved. Therefore, the hydraulic oil should be checked and replaced regularly to ensure that its cleanliness and quality meet the requirements of the hydraulic system.