Background: I just purchased a new air compressor. I was surprised to see that the collar on the quick connect coupling is retracted (I'm used to pulling the collar back to insert the male fitting), but figured that it would latch when the male fitting was placed inside.

Quick connect coupling pre-installed on compressor.

Question: When placing the appropriate-size male fitting into the quick connect, I cannot get the collar to move. The air compressor came with two of the quick connect couplings, and both have the same behavior. What am I doing wrong? Cheers.

Collar will not latch when male fitting is placed

  • I just purchased a compressor - same thing. There is a brass ring inside the coupler that prevents the ball bearings from coming down into their normal position - and letting the outside sleeve slide to its normal position. I saw at least one other compressor in the store in the same condition, so this must be some sort of shipping plug. But the manuals make no mention of it, or how to remove it. I'm still working on that.
    – Ed M
    Mar 18, 2020 at 20:46

5 Answers 5


Some female quick disconnects latch the ring back as you describe. I don't expect you have an issue with the female quick disconnect on the compressor.

I suspect that while your male fitting appears to be the right "size", it is of an incompatible type. There are many different types that appear the same when held at arms length. See this answer for a primer on the various types of quick-connects.


I was sent replacement parts. These fit and worked great. Not sure what was wrong with the other pieces...

  • 1
    Bad Quality Control. I've had cheap Female connectors fail like this. They use 3-5 lock balls under the latch collar that engage the male connector in the groove. If there's a machining bur in the hole the latch ball travels in, it won't let the collar seat or for the ball to engage the groove on the male connector. Also have had such poor machining tolerances that the lock balls fall out underneath the collar. Quality doesn't cost much more so I often throw away the stock junk and convert. Apr 5, 2014 at 19:53

One quick fix that worked for me is to put some oil onto the quick connect coupling, above and below the collar to try and get it to move better and snap forward. After applying the oil, I tried using a flat head screwdriver to gently push the collar forward, which did not work. But i then tried again to attach the male connector, and after trying a few times and pushing firmly, the collar snapped forward. I also noticed that it helps to make sure all air has been let out of the tank before i try connecting the coupling. This also seems to help the collar come forward and the male connector to snap in properly.


I have an 8 gal. Kobalt semi-portable compressor and I had the same issue. As it turns out, it's a quick-connect fitting. So, you don't have to pull it back, you just push the male end in and it locks in. Hope that helps.


I bought a new air compressor (brand: Stark) and had the same issue. There is a copper ring inside the female coupler that seems to block the balls from engaging. I almost wanted to take the copper ring out. Well, I am gad I didn't. All you need is to firmly push in the male adapter. You don't have to push back the collar on the female coupler. This could be a universal female coupler, I am guessing.

  • 1
    No guessing necessary if you read through the other answers. The OP responded that the female connectors were defective and that the manufacturer sent him replacements 8 years ago.
    – FreeMan
    Oct 17, 2022 at 11:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.