Air Compressor question
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Laughing Gas
Joined: Jan 2007
Posts: 765
Likes: 4
From: Fairmount, Georgia
Air Compressor question
I have a small ( 7 or maybe 10 gallon) air compressor that runs fine and has no leak in the tank but does not build pressure. My grandpa suggested maybe it is low on oil but I checked and it is full. It is a Speedaire and I don't know how old it is but I dug it out of a dumpster about 5 years ago and it worked fine then, just had a bent pulley. Anybody got any suggestions?
Fleet Mechanic
Joined: Jul 2005
Posts: 1,464
Likes: 104
From: Staten Island, NY
You say it has no leak in the tank so I assume it used to build pressure. Did it stop building pressure suddenly? If so, take a look at the unloader valve. Its usually located where the line from the compressor head enters the tank and its purpose is to open when the compressor reaches pressure and shuts off so that there is no pressure on the compressor head at start up. If it sticks open, all the air from the compressor is vented and none goes to the tank. They usuall cost a couple of bucks.
Posting Guru
Joined: Jun 2001
Posts: 1,236
Likes: 2
From: Vancouver Island
Checkvalve stuck open or even broken... like the @#$%$ compressor head I bought at a swap meet a couple years ago.
You'd notice if air was coming out the safety valve or someplace like that.
You'd notice if air was coming out the safety valve or someplace like that.
Posting Guru
Joined: Sep 2004
Posts: 1,616
Likes: 3
From: Sapulpa OK
Most likely the valves are broken. Nine times out of ten when capacity drops off thats the reason. If you are sure there are no external air leaks, then pull the head off and inspect the valves. You may get lucky and find a piece of debris lodged under the valve. Just remove it and reassemble and see if performance improves.
Good luck
Steve
Good luck
Steve
Fleet Mechanic
Joined: Jan 2005
Posts: 1,413
Likes: 14
From: cape may county NJ
fixnair]Most likely the valves are broken. Nine times out of ten when capacity drops off thats the reason. If you are sure there are no external air leaks, then pull the head off and inspect the valves. You may get lucky and find a piece of debris lodged under the valve. Just remove it and reassemble and see if performance improves.
I agree most small compressors use reed valves to build pressure and after awhile they break off and being a speedair thats most likely what happened.I have made my own from old motorcycle reeds in a pinch but you might still be able to get new ones
I agree most small compressors use reed valves to build pressure and after awhile they break off and being a speedair thats most likely what happened.I have made my own from old motorcycle reeds in a pinch but you might still be able to get new ones
Last edited by GlennFordx4; Apr 20, 2007 at 06:44 AM. Reason: spelling
