Failures to Look Out for In Hydraulic Seals

A hydraulic piston needs working seals to work efficiently. Fluid leakage is prevented by seals between components as they contain the fluid, especially oil. Seals are categorized into two: static and dynamic seals. Parts that move relative to each other require dynamic seals. The area between the piston rod and the piston utilizes static seals in hydraulic seals as well as in between cylinder bore tubes and the head. Static seals are suitable between fixed components.

Seals are important to the functioning and performance of a hydraulic piston. It is essential to understand seal failure to eke out that extra oomph for machines that utilize a hydraulic piston.

What Causes Seal Failures?

Exposure to abuse and constant use over the duration of the seal’s life will necessitate failure and require replacement. Excessive pressure spikes, improper installation, excessive heat, contamination, among other reasons cause seal failures. The damage hydraulic seals suffer from common failures may be reduced or prevented by having a basic understanding of these failures.


High-temperature exposure hardens hydraulic seals. Stroking operations of the piston may generate heat or high fluid operating temperatures may cause high temperatures. Hardened seals develop cracks and elasticity loss resulting in seal failure.


Considerable damage can be caused by when a seal’s dynamic face becomes worn out. It may wear out due to excessive lateral load or insufficient lubrication.


The operating life of a hydraulic seal requires installation of adequate processes and tools. Dents and cuts can occur from improper installation, affecting hydraulic seal efficiency and contaminating the hydraulic fluid with foreign elements.


A seal’s dynamic side may break off completely, break partially, burn, and develop long cracks when they fracture. It results from the use of sub-standard materials, high-pressure shocks/spikes, and excessive backpressure.


When the piston is contaminated with powder, dirt, mud, or other tiny elements it makes the seal dirty. A dirty seal lowers the efficiency of the seal in terms of contamination prevention.

Chemical Erosion

Corrosive fluids will cause a breakdown of the seal material. Selecting improper seal materials makes the seal susceptible to chemical attack from hydrolysis, oil additives, and/or oxidation. Chemical erosion results in a soft seal durometer, seal shrinkage, seal lip interface loss, and swelling. This failure is highlighted by discoloration of the seal.

The above seal failures can be prevented by selecting seals that meet required application parameters, and having the correct information concerning any machine that utilizes hydraulic pistons. One should be careful to investigate the specific design considerations like the fluid type, cylinder application, temperature range, stroke speed, hardware dimensions, and fluid pressure range before selecting a seal.