Craftsman 33 gal compressor. Build pressure to 80 LBS very slowly, will not turn off, but only stays at 80 LBS pressure. Have replaced piston seal, valve body, & check valve. What now ?

SOURCE: My compressor doesn't build enough pessure.

SOUNDS LIKE THE VALVES IN YOUR HEAD ARE NOT CLOSING ALL THE WAY. THEY ARE MOST LIKELY REED VALVES, THIN STRIPS OF METAL THAT OPEN AND CLOSE WHEN THE PISTON MOVES. MAKE SURE THEY ARE CLOSING ALL THE WAY (NOT CARBONED UP). DID YOU REMOVE THE HEAD AND DID YOU PUT BACK LIKE YOU FOUND IT. NOT TURNED OR FLIPPED OVER.

SOURCE: vertical 33 gal compressor wont build pressure

could be a gaskit or the inlet reed

SOURCE: i have a 5 gal, i hp craftsmen compressor, 3 years

Oil free pumps do tend to blow the piston ring (not too expensive) available at searsparts.com. Remove covers to pump and manually turn crank until piston is at top and look at the condition of the cylinder neer top, If it looks scratched, order cylinder kit with piston ring. If it looks good and shiney, could be the valve plate in the head. There are reed valves that tend to break. Run pump however with covers removed and check with soapy water for air leaks and repair as needed (air leaks under the cover will prevent unit from filling). Good luck

SOURCE: I have a Craftsman model 919.152932 33 gal

Sounds like the reed valves in the head failed. you need to replace the head (usually cheaper to get a new compressor)

Testimonial: "I hated to throw away an otherwise perfect condition compressor, but I had a feeling that was going to be the answer.Thanks for your help."

Brad

• 425 Answers
• Posted on May 18, 2012

SOURCE: I have a 33 gal craftsman compressor when I turn on the relay switch hums but the motor doesn't spin?

I would check the capacitor since it appears that the motor is not locked up. Here is a how to on testing capacitors;


how-to-check-capacitor