A common misconception about hydraulic cylinders is that if the piston seal is leaking, the cylinder will drift down. Fact is, if the piston seal is completely removed from a double-acting hydraulic cylinder, the cylinder is completely filled with oil and its ports are plugged, the cylinder will hold its load indefinitely – unless the rod-seal leaks.

What happens under … Read more

I was asked recently to conduct failure analysis on a hydraulic motor that was the subject of a warranty claim. The motor had failed after only 500 hours in service, some 7,000 hours short of its expected service life.

Inspection revealed that the motor’s bearings had failed through inadequate lubrication. This was the result of the hydraulic motor being started … Read more

Sometime ago I was involved – in a supervisory capacity – in the planned change out of components on a hydraulic machine. The design of the machine’s hydraulic power unit was the all-too-common, cheap and nasty, everything mounted on the tank lid variety. You know the ones – electric motor mounted vertically, with pump submerged in the tank. They’re cheap … Read more