need help fixing air compressor.

[alex carey]

http://www.sears.com/shc/s/p_10153_12605_00915310000P?vName=Tools&cName=Air+Compressors+%26+Air+Tools&sName=Air+Compressors

I was using my compressor on a hollow form, and as it was refilling the air I had used and while refilling the sound the motor makes changed pitch for about 1 second then it went back. This had never happened before. By the time I got to the compressor it was already full, I looked around and it seemed alright. Throughout the night I kept using it and it as the pressure decreased it wouldn't start the motor. Once it got to 20 psi it started to refill again but the pressure never went up. The motor stayed on and the pressure never increased.

Any idea whats wrong?

[Jeff Nicol]

Alex, If the motor still runs and does not run hot or smell bad from over heating I would say the motor is O.K. Is the compressor an oil filled type or an oil less type? In the picture you sent it looks like it is an oil filled compressor. Not sure it the pressure switch is bad or the piston in the pump is bad or the oil level is to low. Take the fittings off after the gauge and make sure the compressor is putting out air, try holding your finger over the open port with all the valves open. You should be able to feel air pressure building and then not be able tohold it back. If the pressure switch is failing you will here the air coming out somewhere thereif a line is perferated for some reason. But the way it sound is one of the check valves in the pump has failed and the air is just not being compressed. I hope I did not confuse you to much but if there is not pressure to the pressure switch it will not shut off the motor when tank is full, or if the pressure switch is letting air bleed out before it gets to the tank. Check out those two things and you should find the problem.

Good luck,

Jeff

[Joe Kaufman]

If the compressor is still able to run, the problem is most likely the reed valves. There is usually a valve plate between the cylinder head and the top of the cylinder that contain the reed valves. one or more may be broken or like the last one I took apart, it injested the foam air cleaner material and gummed up the valves. I was able to clean everything up and reuse the old head gasket. Try loosening the head bolts and tapping the side of the head to break the head free w/o destroying the gaskets. Parts may be available from Sears.

Joe

[Richard Madison]

Agree with Joe. Bad reed valve seems a likely possibility.