Hydraulic troubleshooting is one of our specialties here at Bernell Hydraulics. We love having folks bring in worn or damaged parts and ask us to help them figure out the possible causes of the problem.
However, we don’t want you to have to make the trip in with your part unnecessarily. This occasionally happens with suspected gear pump failures.
A piece of hydraulic equipment has lost pressure. Since the most obvious culprit is the gear pump, the operator immediately removes it. Now, since a worn-out gear pump typically needs to be replaced rather than repaired, this seems like a good idea at first. Operators who are interested in determining why the pump might have worn out may bring it into their local hydraulic parts supplier at this point for some troubleshooting, while others may skip straight to ordering a replacement pump.
However, the pump is not always the cause of your problem. So, you may be making a big mistake and taking out a perfectly good pump if you have not tried this one simple test first:
When any kind of fixed-displacement pump wears out, all of the produced flow winds up going through the clearances into the casing. Because the release of pressure must generate either work or heat, when there is zero flow to the outlet (where pressure would normally be used to generate work) all of the input energy becomes heat. If you had a piston pump, the heat would mostly drain away with the oil through the case drain. But when you have a gear pump, there is no drain and therefore nowhere for the heat to go, so it all stays concentrated in the pump case.
All of this is just a long-winded approach to saying that if your gear pump really is worn out, it’s going to get really hot, really fast. In fact, it will probably overheat in a matter of seconds.
Now, you probably don’t have an infrared thermometer lying around, but there is an easy, low-tech way to test for an overheating gear pump: put your hand on it. Of course, you should not put your hand on the part while it is hot—instead, let the machine cool down, then restart it with you hand on the body of the pump. Raise the pressure and then see whether the pump heats up in seconds.
If it does, it is indeed time to pay a visit to Bernell Hydraulics. We’ll be happy to help you troubleshoot the cause of any premature pump wear you may see and/or order a new hydraulic pump for you.