not enough pressure, sears $130

by Rudy
(PA)

the compressor would not build pressure, I checked the reed valves and there was debris piceces of gasket? cleaned put it back together and it builds some air pressure but not enough keeps running?,

Sears 3 gal compressor will not build pressure

by Kevin
(NY)

I have a small 3 gal Sears compressor that will not build pressure. I took the reed valves out and they were in good condition. I cannot detect any air leaks. The unit looks like new and I hate to throw it out if it is something simple. Not sure where to look next.

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Bill says...

Kevin, it will not build any pressure at all, or it builds to a level before cut out, and then goes no higher?

The difference is important.

The valves look good, and that's a good check. Is air being pulled into the intake while the compressor is running?

Take the line off from the pump top that goes down to the tank (after dumping all air and unplugging) and then start the compressor. Can you stop air from blowing out the line port with a screw driver handle or some sort of plug? If so, then the problem is in the pump, and I would suggest, if not the valves, then a leaking gasket.

Cheers,

Bill

Sears 5 gallon 1 hp model 921.166360 - pressure to only about 50 lb

by Robert
(FL)

Runs and builds pressure to only about 50 lb then no higher and will not shut off. What would cause this and can I fix it? thanks!
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See the troubleshooting section, and follow the links to the pages about why air compressors run and do not build pressure. After reviewing that info, if you have specific questions, write back in.

Cheers,

Bill

Won't pressurize beyond 45 PSI

by Charlie
(Overgaard,AZ)

Has new cutoff/in switch and check valve-still won't build pressure beyond 45 psi. Oiless motor

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Bill says...

Hi Charlie. Your complaint about your compressor seems to be a fairly common one.

In a nutshell, you likely have a valve problem, a gasket leak inside the pump between the intake and pressure paths, a leak somewhere else in the system, with other issues possible, but less likely.

Check out the intake port to see if you can feel air being pulled in, but not puffing back out. If the intake port is just doing that, then I'd look to a gasket, and that means a tear-down.

Go the Troubleshooting page, and click the link to "won't build pressure" and have a read of those pages as well.

Good luck.

Bill