Common Causes Of Hydraulic Seal Failure

Hydraulic seals are ringed components, they form seals in motion applications that involve liquid. These components are very important in the success of reciprocating the motion aided transfer of liquid power to a linear motion. Hydraulic seals are relatively soft and can be composed of a number of materials, such as polyurethane or rubber. Very similar to 0-rings, the hydraulic seal is very durable when used in a proper application setting, but if used in the wrong setting they can cause problems. The main causes of this is contamination, improper installation, chemical erosion and heat erosion.

Improper Installation:

A hydraulic seal that is not installed properly can fail in many different ways, due to unsafe handling, cleanliness, contamination, or even if it is incorrectly chosen for the application.

It is rare for a hydraulic seal to be designed specifically for an application; rather, they usually come in standard sizes and material makeup, applications are designed to comply with them. To prevent mistakes, rather discuss with an engineer or a hydraulic seal manufacturer what the best type of seal is to use for an application.

Furthermore, a proper installation requires knowledge about seals and the equipment. A problem that occurs often is installing a seal upside down, which can result in liquid leaks. If seals are not handled properly, they may tear or nick, which leads to failure.


Contamination occurs when outside jetsam and flotsam is introduced into a hydraulic rod. Mud, dirt, powder, swarf and other small elements can attach themselves to the piston and then dirty the seal. As this seal gets more dirty, it will lose its ability to hermetically prevent contaminants from getting into the piston area. This can be prevented by installing the seal correctly, making sure it is clean upon installation and that the piston area is free from dust.

Heat Erosion:

Heat erosion aka degradation often causes hydraulic seals to bake or melt, after which the seal becomes brittle and cracks apart. The temperature of the application and the continuous friction can considerably decrease the hydraulic seals life expectancy, this is why seals should regularly be checked for evidence of heat degradation.

Chemical Erosion:

Chemical erosion can often be prevented by matching the hydraulic seal material to the different types of chemicals in the application. Depending on the chemicals involved or the type of lubrication used in the hydraulic equipment, hydraulic seals will be better or worse at dealing with degradation effects. A chemical that eats away at a type of material will have less of an effect on another. However, you should remember that heat and contaminant issues result in a more complex decision making process.

At Sealtec Hydraulics we specialise in the manufacture and repair of hydraulic seals. Contact us or visit our website for more information

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