Air chuck keeps popping off valve stem?

Herbie

Rendezvous Conspirator
Hello all, I'm hoping this is a maintenance or usage issue someone can help me with.

I've been happily using my Viair 400p for many years. The included air hose/chuck/gauge has always worked well. Lately, though, I've found that I must hold the chuck tight against the valve stem while filling, lest it pop off. This is new behavior. The valve stems are unchanged, so I can only assume that something has worn or needs adjusting.

Anyone got ideas other than "replace the whole assembly"?

This isn't a huge problem, but it does make airing back up much more tiring work since I need to squat down and hold the chuck tight for a couple of minutes per tire, rather than just occasionally checking the gauge as I used to.

Thanks.
 

Superduty

Adventurer
I'm not familiar with which Chuck viair uses -. No idea what it looks like. However there's typically some type of spring action or some kind of Cam that locks onto the valve stem, my guess is yours is worn. Buy a replacement chuck

Sent from my SM-G973U using Tapatalk
 

Herbie

Rendezvous Conspirator
I may have to, but due to how it's built, that means either losing the deflator capability or starting from scratch. Not the end of the world, but hoping someone has some ideas. As you can see, the chuck is a bit more "integrated" than normal:

5-in-1-Inflator-Deflator-Coil-Hose-Braided.jpg
 

DaveInDenver

Middle Income Semi-Redneck
I know it's not quite the same but on my cheap MV-50 the included hose and chuck were, well, exceptionally cheap. So I ran a tap into the compressor head for plain old pneumatic fittings so I could use clamp-on air chucks on standard hose and quick disconnects like a shop compressor instead.
509466509467
 

Herbie

Rendezvous Conspirator
Yeah, the QD fitting at the compressor-end is standard, and the fitting at the gauge looks to be standard 1/8"npt, so worst case I could add a short length of hose and an off-the-shelf chuck. Guess that's the plan.
 

Herbie

Rendezvous Conspirator
No, mine looks like the picture I posted. Again: the goal was to have the chuck work without losing the built-in deflator function. Looks like that's not possible.

But apparently I'm not a 'legit expo guy'.
 

DaveInDenver

Middle Income Semi-Redneck
If it looked like this:
509514
perhaps you could use a whip hose with a standard chuck.

509515

If it does not look like the gun, then you have a Viair specific something or other and then, no, you probably can't repair it without cutting and clamping in a fitting. That's what I'd try first, just cutting the hose and putting in a barbed fitting (e.g. like the air chuck on the right in post #5).

It don't gotta be rocket surgery.

509486
 
Last edited:

Happy Joe

Apprentice Geezer
Th fitting in the pic looks like the traditional rubber hose insert clamp fitting; never found a good replacement for the short section of rubber/neoprene hose which is likely worn and no longer grips the valve stem... just install a conventional hands free chuck (per DaveinDenver's post, above).

Enjoy!
 

Keith Starr

Inmate #2558516
I had the same exact problem with my Viair compressor, it ended up preventing me from inflating my tires while on the trail, very frustrating. The problem was its ability to grip and stay attached, it wears out, and it no longer put air in. Rather than replacing the gauge/nozzle with another Viair i opted to upgrade to a Milton inflator:


It does not clamp on. They have versions which do clamp on, for example:


Not cheap, but I don't want to be without the ability to inflate my tires because of another failed inflator nozzle thing.
 

luthj

Engineer In Residence
Will the head un-thread from the cylindrical body? If so, you may be able to attach a replacement.
 
OK, so I've used all the chuck types that have been mentioned so far. I didn't like the screw-on that came with the MV-50, becuase there is that bit of air loss as you're taking it off. I went and tapped the MV-50 for 1/4" NPT and with a new air hose, replaced the screw-on type chuck with a clip-on chuck like the one with the longer lever pictured above. I used this for years, but it only has a single tooth that it uses to clip on to the valve threads. As a result, if that clip isn't at just the perfect angle (rotation of the wheel, weight of the air hose) it won't depress the valve core properly and you end up pressurizing your air hose and little else. This is the same problem mentioned by Keith Starr above.

I got fed up and early this year, I bought one of these:
509600
Haltec H-5265 Standard Bore Lock-On Air Chuck

It's designed like a quick disconnect. It features three spring-loaded teeth to grip the threads of the valve. It doesn't suffer from the same hystrionics of the single-tooth lock on chuck and you just pull the lock sleeve back when you're done and it pops right off. I've been using it for a few months now and for me, it's been a perfect solution. Can't recommend it enough.

OP, I know the premise of your question was not to replace the assembly, but I think in the long run you'll be happier with having done so. If you don't want to replace the hose, I'd still get this chuck and use a hose adapter and clamp (like that also pictured above) to make this work for you.
 

WOODY2

Adventurer
Hello all, I'm hoping this is a maintenance or usage issue someone can help me with.

I've been happily using my Viair 400p for many years. The included air hose/chuck/gauge has always worked well. Lately, though, I've found that I must hold the chuck tight against the valve stem while filling, lest it pop off. This is new behavior. The valve stems are unchanged, so I can only assume that something has worn or needs adjusting.

Anyone got ideas other than "replace the whole assembly"?

This isn't a huge problem, but it does make airing back up much more tiring work since I need to squat down and hold the chuck tight for a couple of minutes per tire, rather than just occasionally checking the gauge as I used to.

Thanks.
I know this sounds elementary but reaching out to Vair might prove to be productive? Many company's realize the value in proactive customer relations/ service. Just my $.02
 

JaSAn

Grumpy Old Man
leaveyourego, thanks for the link. Did you find going to a regular air hose improved flow?
 

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