Directional Valve Spool Configuration and Cylinder Drift

Hydraulic Solenoid Valve (Bosch Rexroth)In response to my previous post about troubleshooting hydraulic cylinder drift, a couple of our members thought the influence of valve-spool configuration on cylinder drift warranted discussion. Charlie Field from Perry Slingsby Systems in the UK sent me this message:

“By far the most common reason for cylinder drift is the DCV controlling it. Closed to actuator spools almost … Read more

How To Nail Hydraulic Cylinder Leakage

The Hydraulic Troubleshooting HandbookA 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

An Essential Step to Avoid ‘Infant Mortality’ of Hydraulic Pumps and Motors

barrel_A4VI 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