Bostitch compressor will not build any pressure

Bostitch is a popular DIY air compressor. This page has to do with reasons why a Bostitch compressor will not build any pressure. Comments and responses are below.

At the end of this page is a form where you can add a question if you would like.

My Bostitch air compressor will not build any pressure or very little?

by Ben Jones
(Morrisdale, Pa)

Oil free compressor does not build any pressure or very little?My bostitch pancake air compressor started by not shutting off when it hit the designated air pressure (continuously ran unless you manually shut off), but now it turns on and sounds weird and does not build any pressure or very little. What would you say is wrong?

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Ben, first off, that the compressor didn’t shut off at normal cut out pressure and you had to shut it off manually suggests the pressure switch has failed.

The weird sound you are hearing might be intake valves, pressure valves, blown gasket, motor failing, pump mechanical issue… it is pretty hard to tell from here.

When you say “but now it turns on and sounds weird ” do you mean that it is cutting in at the normal pressure setting, the compressor is running at the point, but no air pressure build up in the tank at all?

Can you please post a comment with more details?

Bostitch 6 gal oil-less air compressor won’t fill to full pressure

by Jeff
(Conway, sc)

My Bostitch 6gal oilless air compressor will run fine to around 50 or 60 psi, and then continue to run without gaining more than a couple psi.

No audible air leaking, and the tank continues to run just as before.

After a couple of minutes, I turn it off, drain it, then repeat and get the same result.

60 psi is about the max I have gotten. Any thoughts would be greatly appreciated as this compressor is very pricey and too expensive to replace. I’ve also taken the piston head apart and all the air valves are fine.

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Jeff, good that you checked the valves. Glad also that they are fine. There are other issues relating to air compressors that run and don’t build pressure.

Shut it down, empty the tank, remove, clean, and replace the tank check valve. Any change?

Assuming that the power supply hasn’t changed, you may be experiencing a pressure related gasket failure, or you might still be having a valve fail under load.

See the site map page, under the Troubleshooting category, for links to more info on why an air compressor will run and not build pressure.

Bostitch model# CAP60P – Won’t build pressure?

by Lane
(Alabama)

Bostitch model# CAP60P – OF

Unit won’t build pressure.

Main supply line to the tank at the non return valve gets real hot.

The compressor also has a higher pitch sound. The non return valve seems to be working. I’m wondering if it’s the valve plate assembly at the head?

Lane
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Lane, if you have air huffing out of the intake port on the pump head, then, for sure, you have a valve leak. Air is bleeding out fast enough that the compressor tank pressure can’t build past a certain point.

The pressure valve failing could be the cause, as well.

All compressor air lines from the pump head to the tank get too hot to touch. That’s why they are made of metal, so that symptom may not provide any clue.

Don’t know about the sound change, though that might be because of the valve issues, or an internal gasket leak at a certain pressure, or it could be that the compressor is running too long and overheating… it’s supposed to shut off fairly quickly after the pressure switch turns it on.

To correct these you will need to tear down the pump. You might as well have a valve kit and gasket kit on hand when you do. If the valves are at fault, you will have the valve kit ready. The process of tear down will likely destroy any gaskets, so not only will you not be able to tell if they were at fault, but you will need to replace them anyway, I suspect.