When you think of a hydraulic oil leak, you might picture a dripping hose fitting or valve, and a puddle of fluid resting on the floor. In some cases, however, less obvious leaks might be making your entire system less efficient. In addition, these hard-to-detect internal leaks can damage your fluid power system if left unresolved.

What Causes Internal Hydraulic Fluid Leaks?

There are a number of factors that cause internal leaks, including:

  • Worn component surfaces
  • Worn and/or damaged seals
  • Badly designed systems
  • Manufacturing or rebuild mistakes
  • Using the wrong parts for the job.

Component wear & tear is the most common cause of internal hydraulic leaks, and those kinds of leaks come on slowly as equipment breaks down over time. Component surfaces begin to wear away and spaces emerge where fluids can leak inside the system.

How Damaging Are Internal Leaks?

Leaking hydraulic systems suffer from low performance and efficiency, and the problem can become worse over time slowly or quickly depending on the cause of the leak.

When internal “clearances” – the space between two parts in a system – expands between a valve body and the spool on a spool valve, for instance, the system can become unstable, resulting in control issues and bad efficiency caused by energy loss.

Hydraulic pumps and motors can be a source of internal leakage and are often where major leakage problems occur. Space between components allows fluid to leak within the system and can create slippage, which makes the fluid power system less efficient.

Finding the Source of the Hydraulic Leak

When you suspect an internal leak, it can be hard to troubleshoot the cause and pin down the exact source if its not a problem you’ve faced before.

A good first step is to install flow meters throughout the hydraulic system. Flow meters help detect the leak location.

Next, perform a bench test. Bench tests will often reveal leaks around hydraulic cylinders and control valves.

Ultrasonic measurements are also key to detecting internal leaks, as they provide a feedback window into the system’s internal workings.

More Ways to Improve Leak Detection

Keeping good records and close surveillance to monitor leakage within hydraulic systems is a good way to detect long-term trends and stay ahead of damaging internal leaks.

Matching this information with a maintenance plan aimed at catching leaks early can help keep your system efficient and reduce the need for repairs.

Fixing Found Leaks

As mentioned previously, component wear and tear is the most common cause of an internal leak.

Replacing the worn part(s) will often fix a leak caused by the excessive space / clearance between two parts that should be sealed tight. On occasion, however, a major part may need repaired, remanufactured, or replaced.

If any parts in question show signs of premature wear, it’s worth investigating to find if that wear is the cause of a leak following the steps outlined above. In some cases it may be found that an additional source is at play – perhaps wrong hydraulic fluid, contamination by abrasive particles, or higher-than-recommended  operating temperatures are the underlying culprit.

Think You Have a Leak? Prompt Attention is Required

Unintended internal leaks result in reduced performance, low efficiency and poor reliability. For these reasons, leaks require immediate attention. While downtime for finding and repairing a leak may seem expensive, it will save money over time.

Cory Gilbert
Cory Gilbert

With a personal goal of taking care of the customer at all costs, CEO Cory Gilbert has been a driving force behind the high level of customer satisfaction at Hydraulic Parts Source since 2009. Cory has a “whatever it takes” attitude and helps maintain a customer service team that is accountable, honest, efficient, and hard-working. One of the first things you’ll learn about Cory in his professional life is his belief that “customer relationships are everything.”

Cory is a graduate of Alma College with a degree in Finance and Marketing. Outside of work, he enjoys spending time with friends and family. He is a sports fan who also enjoys golfing in his free time.