Hydraproducts Blog

Get in touch today to discuss your requirements

Call: (+44) 01452 523352

Hydraproducts Blog


All the latest news and information from Hydraproducts.

How to Put a Stop to Hydraulic Leaks ben lee

Hydraulic systems are renowned for leaking oil. The trouble is, that oil costs money and needing to continually top up becomes a major expense for many hydraulic equipment owners. Here are some interesting but slightly alarming stats from the NOAA (National Oceanic and Atmospheric Administration). Although they are located in the USA, these stats will give you some idea of how much oil is being consumed and also used as replacement.


According to the NOAA more than 2.65 billion litres are entering the environment on an annual basis. Approximately half of this derives from illegal disposal, and 370 million litres of it comes from leaking hydraulic hoses. It’s estimated that it takes just one litre of oil to pollute up to 1 million litres of water so these are stats that should be taken seriously.


If governments were to get serious about pollution and begin to charge for any discrepancy between oil delivered and oil disposed of (measurements would need to be taken by a governing body or by oil delivery companies), then companies could be in for a financial shock. It would certainly become more pressing to repair oil leaks.


What puts a lot of companies off from fixing leaks is that there is always downtime involved. This avoidance will allow leaks to increase to the point where the price of the replacement oil is almost equal to the cost of downtime and repairs.


Here are ways that you can stop those leaks.

Re-engineer. Without connectors, a hydraulic system cannot leak. However, a system has to have some connectors, but through the clever use of integrated hydraulic circuits using valves and manifolds, they can be greatly reduced.

Although it would usually be the machine designer who would apply this type of technology, if you have a hydraulic system that has many connections with line mounted valves then it makes sense to replace these to reduce the amount of potentially leaking components and joints.


Use decent connectors. The most unreliable connectors are those with a thread. For example NPT and BSPT both have threads and that can mean a leak path. When tightened, the threads become deformed and then any tightening or loosening can cause further damage and more leaking.

Opt for the elastomeric seal that can be found on the ORFS, SAE, BSPP and UN-O-ring connectors for a significantly superior seal. In summary, you’ll gain far better results if you replace connectors that are pipe-threaded with those that use an elastomeric seal.

The most commonly found hydraulic connection is the JIC 37 flare. This uses a metal to metal seal that does not always remain leak free. In this case you might want to install a conical washer between the flare and the joint’s nose.


Tighten Them Properly — incorrect torque can be blamed for most leaks from 37° flare joints in addition to compression-type tube fittings. The seat contact is inadequate. A torque that is too high can cause damage to the tube and ‘crush’ the ferrule.


Eliminate Vibration — if there is something that can cause stress fatigue, it’s vibration. If there is vibration, it’s key to check what the cause of this is. It could be necessary to install rubber mounting blocks to enable vibration to stop travelling between valves, the hydraulic power unit and the reservoir. Also ensure that clamps support tubes and pipes.


Keep The Machine Cool - keeping fluid within recommended operating temperatures is elemental to enabling components to have a full service life. Going over 85° C (185° F) can reduce service life rapidly. Even going over temperature on a single occasion can damage rubbers and seals and deliver a number of leaks. This is another reason why a hot running system is unreliable.

By using these approaches to reduce the number of leaks on your hydraulic system you can reduce costs and lower the risk of extended maintenance downtime.

Comments are closed.