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Fitting Identification

grtpumpkin on Fri October 09, 2009 7:07 PM User is offline

Year: 000

What is the proper technical name for this fitting? It is for R134A and R22 systems? This is on a 30lb tank and has no valve core. My yellow hose from my manifold gage set is too large and has the plunger for the valve. What is needed to adapt this to my yellow hose? I'm trying to learn all this ac stuff.

HVargas on Fri October 09, 2009 7:18 PM User is offlineView users profile

It will be for either R134a or R22. R12 and R22 share the same size fitting. In either case it is a 1/2" ACME thread fitting. Odds are your gauge set is for R12 and the tank is threaded for a R134a charge hose.
82634 - Service Port Adapter


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Edited: Fri October 09, 2009 at 7:18 PM by HVargas

grtpumpkin on Fri October 09, 2009 8:00 PM User is offline

The fitting on the tank is the same exact fitting as on all 3 lines at the gage set end. The gage set is for R134a. Just trying to adapt it to mate to the yellow line from the gage set or to my vacuum pump. Is there an adapter that would thread on to this tank fitting that would have a valve core in it and would connect to the yellow line? I also need to connect the yellow line from the gage set to my vacuum pump. Not sure what the thread size or type is called on the hoses at the ends opposite the gage set. My gage set has thread on snap fittings to allow connecting to the Hi & low sides of the vehicle. These snap fittings thread on to the red and blue hoses and seal with o rings.
This is getting confusing. No??

I see your link now. I thought R12 and R134a were the same. This would explain some confusion.

Edited: Fri October 09, 2009 at 8:30 PM by grtpumpkin

grtpumpkin on Fri October 09, 2009 9:17 PM User is offline

Is there a fitting to convert from the 1/2 " ACME directly to the snap fittings of the R134a? This would obviously be 2 different adapters. One for the low & high side. I'm actually also going to be working on an R22 system for the house and I would like to connect my gage snap fittings to it.
This would be the same scenario as converting an R12 system R134a, but we want to be able to use the quick snap connections of the R134a gage set instead of the threaded connections.

Does this make sense?

mk378 on Fri October 09, 2009 9:46 PM User is offline

The thread on your cylinder fitting, like most 30 lb cylinder fittings, is known as 1/4 inch flare. These fittings are used with most refrigerants including R-12 and R-22, and stationary systems with R-134a.

Cylinders of R-134a sold for automotive use have 1/2 inch acme threads. These threads are larger diameter and coarser thread pitch. The end of the fitting is flat rather than conical. You can actually buy R-134a in either type of cylinder depending on where you buy it, it is exactly the same gas just different fittings on the cylinder. Cylinders don't have shrader valves in the fitting, they are turned on and off with the hand valve. The valve depressor in a hose will not pose a problem making up to a fitting that has no shrader valve.

An automotive R-134a manifold set interfaces to the car with snap on quick connect fittings and to the vacuum pump or refrigerant cylinder with acme fittings. In auto work there is never a need to adapt from acme to quick connect. A lot of the low-cost manifolds are sold as dual purpose. They typically have flare fittings on all 3 hoses but are supplied with 3 adapters for work on R-134a cars. Leaving the adapters off makes it compatible with R-12 systems and cylinders.

The adapter from a acme hose to a flare vacuum pump is commonly available, it will also work to connect cylinders. Note that R-12 and R-22 react chemically with the PAG oil used in factory R-134a cars and form a sludge. If you're going to go back and forth you should flush the manifold and hoses to get the PAG out. It works better in the long run to just buy another manifold and dedicate it for R-22/R-12 service than to keep messing with adapters.

You could just put a couple of car conversion fittings on your house system and connect the snap on fittings to it but that is asking for trouble. Realize that R-22, R-12, and R-134a all have completely different properties and must never be mixed in a system, it simply will not work. Thus the different fittings.

Edited: Fri October 09, 2009 at 9:50 PM by mk378

grtpumpkin on Fri October 09, 2009 11:37 PM User is offline

Can I get an explanation of what this adapter #90338 converts. Does it covert screw on to snap fit?

Adapter 90338

mk378 on Sat October 10, 2009 12:00 AM User is offline

That is used only on some of the last of the R-12 cars made by GM, 1991 to 1993 models. GM used a proprietary "deep throat" fitting on the high side. It won't fit anything other than old GM cars.

This conversion fitting and its companion the 35-16363S are I think what you're looking for.

Edited: Sat October 10, 2009 at 12:08 AM by mk378

NickD on Sat October 10, 2009 7:18 AM User is offline

With gases in general, different fittings are used for practically all different gases so you do not mix the or use the wrong gas. Often wondered about these alternative refrigerants, they sell their magic cans of stuff with different fitting on those plus adapters for your MVAC fittings, but don't sell anything for your gauges so you can hook up to them.

But I think this is what your are looking for.

But don't ask me where I got it from, have so many electrical, electronic, and gas adapters, my brain is like scrambled eggs. It was in my box labeled AC crap. Have to make sure it gets back in that box or will never find it again.

grtpumpkin on Sat October 10, 2009 11:09 AM User is offline


Thanks for your input. Yes those are the ones. I just ordered them on here. One little project I'm working on is a Home window unit that seems to have recently lost it's charge. I want to be able to hook up my gage set to these piercing valves and do some diagnostics.

Mind you this is just for fun and to see if I can fix it. All in all it would be much easier to go out and buy a new air conditioner. Where's the fun in that? My next dilemma will be to try and purchase some R22 refrigerant.

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