919.167783 compressor will not build pressure

by Chad Zeilenga
(Crete, IL)

I've read through many of the posts here and can't seem to figure out my air compressor issue.

It started with the compressor struggling to reach the 150PSI cut-off.

So I inspected and found the cylinders were heavily scored and the rings had taken a set.

I installed ring & cylinder kit K-0650 & K-648 to resolve for both the HLP & HHP.

After putting back together with new gaskets & o-rings the compressor would only reach 30PSI and then just keep running.

It never shuts off.

I next inspected the reed valves and found some very small gaps between them. Although I didn't feel any air moving out of intake, I ordered new valve plates and installed those with a fresh gasket that I cut-out from material. Put it all back together and torqued it down and still have same issue.

With the compressor off, it does not bleed down or leak. Just sits at 30PSI. I felt near the Pressure Relief Valve while it was running and couldn't feel any air escaping.

At this point, the only thing I can think of is the Choke valve is not sealing properly.

Is there anything else it could be?

Comments for 919.167783 compressor will not build pressure

Click here to add your own comments

Apr 10, 2015
I think I found it
by: Chad

Last night I re-inspected the valve plates. Both were oriented properly.

Next I charged up the compressor to the 30PSI and shut it off. Then I proceeded to spray down the routing from the intake, around the valve plates, lines etc. When I sprayed down the choke valve I found that there was air escaping through the threads of the fitting. Then I removed the inlet tube and found that there was air escaping through the check valve. Ordered a replacement and will install. Thanks for your input & time!

Apr 09, 2015
Not sure you understand
by: Chad

Hello Bill,
I'm not sure you understand my issue as I explained that the compressor is not cutting out. It will run up to 30PSI tank pressure and then will continue to run without the tank pressure increasing. When I turn the compressor off, the tank pressure does not drop, even overnight. This tells me that there are no-leaks in my system and I'm not sure what spraying down with 10:1 soap will tell me. Are you suggesting that pressure >30PSI can get past the check valve and is bleeding off the unloader valve while the compressor is running? How do I check the function of the check valve? When I removed it, it appeard to be making a seal, but perhaps the spring is weak?

I will take the valves back off and ensure that they are oriented correctly when I re-install them. If I understand correctly, the valves can be installed 180° from the correct orientation. Is there anything else that could be incorrect? I only have a gasket installed on the HHP valve plate as the HLP didn't have one when I disasssembled.

Apr 08, 2015
by: Doug in s.d.ca

You may have to remove or block airflow from the fan temporarily.

You may also be able to put some kind of handle where the fan goes so you can turn it manually while looking for leaks. Otherwise, put on soap, run for just a second or so and you will be able to see any external leaks.

But I think you may have misassembled it, such that one of the valve plates is your culprit.

Apr 08, 2015
Leak test
by: Bill

Let the compressor fill as much as it can to cut out, then, when the compressor is not running, soap all the joints.

Typically it's 10 parts water to 1 part liquid dish soap.

If there is a leak, bubbles will form wherever air is escaping.

Still sounds like you have a tank check valve leak to me, and that air would be escaping out the unloader valve all the time the compressor is off.

That the leak stops at 30 PSI suggests to me that higher pressure can blow by the seal, but not lower.


Apr 07, 2015
When to test?
by: Anonymous

Should the compressor be running while I test with soap? With the fan blowing while the compressor running, I would think that the air would blow the bubbles away. The compressor doesn't leak down below 30 PSI when it is off.

Apr 07, 2015
check or choke
by: Doug in s.d.ca

Also, these craftsman compressors have a "choke" valve as its listed on the parts list.

You're right, but they are wrong. Look at any (well, most, anyway) other diagram and they call it a check valve, or valve check.

There is a thing called a choke valve, but this isn't it.

Anyway, hope you find your leak.

Apr 06, 2015
by: Chad

i haven't tried soap, but that would be a lot less $ than I've spent so far. It's not bleeding down while shutoff.

Also, these craftsman compressors have a "choke" valve as its listed on the parts list.

Apr 04, 2015
At this point, the only thing I can think of is the Choke valve is not sealing properly.
by: Doug in s.d.ca

You mean the check valve? Not if it's holding pressure in the tank.

Have you tried using soap solution around the head and connections ( like the interconnecting tube )?

Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Craftsman Compressor Issues.