Why do hydraulic cylinders start leaking?

Seals play a major role in hydraulic cylinders – they contain the fluid and prevent the leakage of fluid. The seals for a rod sealing system protect the reciprocating motion for the piston rod and gland.

Here are some types of seals you will normally find in a Hydraulic Cylinder:

Piston seals — keeps oil on the work side of the piston. Prevents oil travel between cylinder sides.
Rod seals — prevents any leakage from inside the cylinder to the outside.
Buffer seals — absorb changes in pressure when working with high-load conditions. Normally found in front of the rod seal.
Wiper seals — prevent any outside contaminants or debris from entering the cylinder system.
Wear bands — guide the piston and rod. Also prevents metal to metal contact.

Listed below are some common reasons for seal failures:

Hardening — too much heat being generated from a high-speed application or environmental conditions surrounding the cylinder.
Wear — excessive wear due to lack of lubrication.
Contamination — any small pieces of metals or debris entering inside can damage inside components.
Fracture — resulting from excessive back pressure
Improper Installation — not using the proper tools to install seals can lead to damage and leaks. Most manufacturers offer installation tips, including surface specs and groove dimensions.