Chances are, your hydraulic hose is not leaking because it’s defective. Most hydraulic hose leaks are caused by using the wrong type of fitting or installing them incorrectly. Additionally, if an O-ring is missing or damaged or if over-under-torquing the connections has occurred, the seal may not be aligned correctly and even worse, the threads might be damaged.
Some types of fittings leak more than others, as well, especially after they’ve been removed and reinstalled. For example, removing and retightening an NPT or JIC fitting can strip its threads, essentially causing a pathway for hydraulic oil to drip through. These designs are usually leak-tight upon first installation, but really should not be removed and installed again. If there is a need to remove an NPT or JIC fitting, a completely new fitting assembly should be installed.
A simple solution is to use an O-ring fitting. These soft seals create positive seals that do not leak. However, these are not fail-safe if not selected correctly. If the O-ring is not compatible with the media being conveyed or for the system operating temperature range, they could break down and fail. Ensure the entire system is designed so that all of its pieces and parts are compatible and will work together in the most efficient manner.
Installation and routing can also cause hose leaks if the hose is not long enough. If a hose is too short, it cannot expand and contract with the constant changes in pressure and temperature. This will cause strain on the fittings, hose covers and reinforcement, causing them to leak.
If hose supports and clamps were not installed into a system, vibration could cause the hose assemblies to fail. Clamps and brackets reduce stress on the fittings and support the heavy hose as the fluid is pressurized.
Contamination, the bane of all hydraulic systems, can damage the inner tube of a hydraulic hose and result in leakage. To avoid particles in your hydraulic hose, all hose assemblies should be cleaned before fittings are installed, either by flushing or using high-pressure projectiles. Once a hose assembly is cleaned, use caps and plugs to keep them clean until they are installed in the system.