How to Classify Hydraulic Oil Leaks

Slow leaksOne of our members wrote me with the following question:

“We are trying to give one of our customers a short definition of what constitutes a hydraulic oil leak. Is there a standard or a general definition of what constitutes a hydraulic leak?”

It’s not rocket science. In the case of a hydraulic system, any hydraulic fluid that appears on external surfaces can and should be classified as a leak. With one important exception, which I’ll get to in a minute.

By way of external arbitration, in their maintenance manuals the U.S. Army defines three classes of leaks:

–Class I: … continue reading »

Reading This COULD Save Your Life!

FirstAidCrossA highly qualified, intensive care doctor is struck down with appendicitis. So he undergoes keyhole surgery at the hospital where he works. He is now a patient in his own hospital. In the recovery room, post surgery, he is awake but starts to feel light headed. A nurse takes his blood pressure and it’s way down. This triggers an emergency response.

The medical emergency team arrives at the patient’s bedside. Being a doctor himself, the patient argues with them. He can’t believe he’s having a heart attack, because he doesn’t have any chest pain. But the attending emergency doctor shows … continue reading »

Hydraulic Motor Case Drains Optional, But ALWAYS A Good Idea

While absolutely essential on a piston-type hydraulic motor, an external case drain line is usually optional on gear motor designs–external, internal and gerotor/geroller. These types of motors don’t have a large-volume case or sump like piston motors do. But they do have internal leakage which by design, usually accumulates in a small cavity just behind the shaft seal.

By installing a high-pressure shaft seal and two check valves as shown in the schematic diagram inset above, internal leakage is drained via the return line–something that’s not acceptable for a piston motor or pump!

So the presence of a high pressure … continue reading »