Compressor Does Not
       Build Pressure

This is another in a series of pages about why an air compressor does not build pressure.

Here is where you can post question of your own, or offer advice or a comment.

Question: The air compressor wont pump above 60 psi ~ a solution by aaron (green bay wi usa)

I have a Central Pneumatic 94667 air compressor from Harbor Freight. After about a years use, it ceased to bring the pressure above 60 psi. The red arrow in the photo identifies the area of the broken gasket.

Broken gasket

After reading some of the posts by others, I figured it should be a simple fix, by cleaning up the reed valve. Upon removing the head of the pump I saw a small amount of foreign material pressed to the plate that mounts above the reed valve.

I thought I had it fixed so I reassembled the pump. 60 psi. I disassembled it again and this time I also removed the orifice plate from the head of the pump. That is where I found the problem, and the source of the foreign material above the reed. Hopefully this helps others.

Comment about compressor wont pump above 60 psi May 20, 2012 by: Derek K

Went to the parts store and picked up some Fel-0Pro Rubber Cellulose sheet (Part Number 3075). Make up two new gaskets and works great. Used some paper and pencil to trace the parts and cut our a new set. Took about a hour to clean and make new and parts where $7 Works like new now. Best of luck out there.

Comment compressor wont pump above 60 psi Mar 07, 2012 Same problem but more by: Smithaj

I have the same compressor but my valve reed is broken, the same issue occurs (do compressor wont pump past 28psl) but finding a replacement is harder that it looks. The compressor is discontinued. Where can i find a replacement reed?

My response to air compressor wont pump above 60 psi

Your request is posted for advice from folks that might have parts. Another visitor suggests that you can use the blade from a paint scraper, cut to size of course, and that the flexible nature of the scraper blade makes a good reed. Haven't tried it myself.

New question: Compressor will build and stop at 40 psi? by g (Prattivlle, al usa)

Do i need to change the regulator, change the valves, the gauges?

My response to Compressor will build and stop at 40 psi? Hi there, G! I wouldn't change anything just yet. When your air compressor stops, what stops it? Is it going off on some sort of overload, does it blow the breaker, or does the pressure switch trip to off?

When it turns off, is power still flowing to the motor from the pressure switch? Please post your response as a comment so I can follow the thread.

Response to stops at 40 psi? May 31, 2011 by: G

It just appears to keep running. it is at my sons house and I'm merely trying to help him out. I plan to move to my house to REALLY check it out. Thanks for your response and i will keep you posted.

My response to the comment If it keeps running, and won't build pressure past the 40 PSI mark, first things to check are the intake valves, and then, if no other leaks, you may have a gasket failure inside the pump.

Another comment compressor will build and stop at 40 psi? Mar 30, 2012 by: TB

The compressor will continue to run until manually shut off. Pressure in the tank only builds to 35-40 psi max, but when shut off does not leak out. I think the check valve is ok. The unloader valve may be ok too but what are the steps to check if it never reaches the cut out pressure to vent itself? I have not checked the intake valve yet either. any other suggestions?

My response to the new comment Yup, see the troubleshooting section on the site map page about why air compressors will run and not shut off... also, why they only build to a certain pressure and stop building pressure, but still continue running. Lots of things to check there. when you have reviewed the list and applied it to your air compressor, post a response telling me what you found, OK?

New question: Compressor dont pump up proper? by jeremy

It works great other than it will only pump up to 25 psi, still runs dont shut off, but wont pump to max pressure?

My response to Compressor dont pump up proper?

Hello Jeremy. Is air getting pulled into the intake port while the compressor is running? If not, or if it's perhaps "huffing" out, that would suggest an intake valve problem. The other common cause is a failed gasket inside the pump, so if it's not the intake valve, and the pump runs as normal, you may have that gasket failure. To identify that problem for sure, and for a repair, will reuire a pump tear down.

New question: Kobalt electric air compresser parts? by: david

i have the kobalt electric air compresser its a 1.5 hp 26 gal. it only builds pressure to 90psi. i took it apart and found its the piston seal . now the question is where do i get that seal its not in the parts manuel i got ?

My response to Kobalt compressor parts? David, you need to know the compressor model number. Visit your Lowes store and ask if they can supply the parts, or, where they get their Kobalt air compressors fixed under warranty. Those folks could have parts for you.