Despite the first assumption of a hydraulic hose leaking being that it’s defective or that there’s a crack in the line, the most common cause is usually using an incorrect hydraulic fitting or installing it improperly. Missing or damaged O-ring, or over/under-torqued fittings can also cause leaks as the seal will not align properly. Over/under torquing can lead to damaged threads, which almost certainly leads to leaks. Hydraulic fittings are a more frequent source of leaks it’s easier and cheaper to replace a fitting than to attempt a repair.

Do not ignore the leaks

Even the smallest leaks could be a sign of a broader problem within the hydraulic system. Long-term negligence of leaks can lead to broader problems and even complete failures of the system leading to longer downtimes. Leaking fluid can also cause contaminants to enter the system. Even small dirt particles or air in the system can cause failure. Therefore, immediately repairing hydraulic fitting leaks or any leaks found in the system is critical to its service life.

Finding the source of the leak

It’s important to check the entire assembly including all components and hoses along with the fitting. This can help find the source of the leak as it may not be the hydraulic fitting. Changing or repairing the hydraulic fitting before checking the entire assembly can lead to the leak and issue continuing.

Some hydraulic fittings may leak more than others

Removing and reinstalling fittings can make them prone to leaks and defects. O-ring Face Seal (ORFS) and O-ring Boss (ORB) fittings are fine to reinstall if the O-ring is still intact and in good working condition. However, certain hydraulic fitting styles such as JIC or NPT can end up being stripped of their threads with reinstallation or retightening causing leaks and defects. It’s therefore recommended that JIC and NPT fittings should be replaced with a new fitting when removed instead of reinstalled.

Conducting a hydraulic repair safely

Before attempting to repair a hydraulic leak, be sure to depressurise the system. This will help avoid dangerous and explosive discharge of hot hydraulic fluid which can cause damage and harm to both the system and persons.

Safety precautions when working with hydraulics

Along with depressurising the system, it’s important to remember to never use your hands (with or without gloves) to check for hydraulic fluid leaks. This is because the fluid can reach very high temperatures which can cause serious injury and burn on contact. Also if the fluid manages to reach the bloodstream via an open cut or wound it can cause a dangerous infection leading to serious health complications or even death in extreme cases.

Summary

• Do not overtighten fittings
• Check and replace O-rings on hydraulic fittings
• Use a torque wrench whenever possible. This will help ensure that the fittings are connected at the proper pressure and torque.
• Use the correct hydraulic fitting type.

In addition to all of the points above, make sure to use hose clamps to hold the assembly safely in place.