Compressor wont shut off only gets to about 100psi I can also hear a air leak under the cover but if I manually turnit off the air leak stops and it hold air do you think its the tube seal.

SOURCE: i hear an air leak and it won't compress beyond 100 psi?

hi mate from the pump unit to the tank you may find a valve on the tank with a pipe from the pump unit undo it and replace the rubber inside or turn it around also it may be a gasket blown check around the cylinder for any air this is exacly what happened to me and it was a gasket good luck

SOURCE: Air Leak From Pump Head on Porter Cable C2001 Pancake Compressor

The real question is where exactly is the leak coming from. Compressors have a pressure release valve designed to let the pressure off of the compressor motor so it can start when there is pressure in the tank. This valve is often the culprit and fairly easy to replace. You can order it direct from porter-cable online. Just in case double check the drain petcock sometimes these get worn and won't close completely and can easily be over looked when trouble shooting.

Brad

• 425 Answers
• Posted on Jul 16, 2011

SOURCE: My compressor since new, at times will leak air

There is a check valve that is wired into the on off switch. If there are no air leaks when the unit is not running then it is normal. The other possibility is a leak where the rubber hose conncets to a metal tube inside the plastic housing.