View Full Version : Air Compressor takes a long time to fill

01-30-2008, 08:50 AM
When I turn on my 5 gal Sears compressor, it takes about 5 minuetes for the unit to shut off. Any body know what I can check for? Its about six years old and see infrequent use.

01-30-2008, 09:16 AM
Is that while filling just the compressor or filling your airlines too? How long did it used to take? Is this an oiless or oil type compressor? Is it direct drive or does it have belts? Does it seem to hold pressure once it finally does fill up? Probably first thing I'd do is make up some soapy water in a spray bottle & spray around all fittings & connections to check for leaks. If there isn't any it is a problem with the pump or maybe a belt slipping.

01-30-2008, 08:12 PM
If you use it a lot, it is probably getting worn out. If you cannot find a leak or something obvious, the pump might have a lot of blow by or bad valves.

01-31-2008, 06:40 AM
When I notice mine taking longer than usual I replace the valve plate and the piston ring-- both available from for reasonably cheap. Most often the valve plate has a broken reed/flap valve when this happens.

01-31-2008, 06:43 AM
Rickstir - is this a new problem, or has this compressor always been slow?

Piston or diaphragm compressor? (oil-lubed or oil-less)

01-31-2008, 07:17 AM
Thnaks for the great responses.
I will try to find a leak this week-end.
It has been slow about 6 -8 months now

I will try to get a diagram onilne so I can find the valve plate.

This is an oil-less compressor.

02-02-2008, 11:50 AM
Rickstir, the oil-less compressors get away with being oil-less by using a plastic piston. The do wear out. A friend of mine had this exact same problem wit his Sears. He bought a "rebuild" kit for about $30. A very simple job, and it now builds the correct pressure, and charges the tank much more quickly.