R12 hoses with R134 Adapters

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R12 hoses with R134 Adapters

Postby wiztom » Sat Jun 09, 2018 4:16 pm


I am trying to add R134 to my sons 2005 Miata. I have an r12 guage and hose set. I have R134 adapters that have no schrader valves on the hose side, however the hoses have schrader valves on the adapter connection side. I am trying to add freon but it seems to be only charging the hose. Do I remove the schrader valve from the hose? If so whats the best way to do that?
Any guidance appreciated.
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Re: R12 hoses with R134 Adapters

Postby Cusser » Sun Jun 10, 2018 6:45 am

Post good photos of the ends. I bought adapters about 15 years ago, and they've worked fine.

Why not use loaner R134a gauge set from Autozone? I used such set last year when 100 miles away from home when I developed a pinhole in a rubber line and had to replace that.

Remember: use NO SEALERS, just pure R134a. Refrigeration oil (correct type and amount) and UV dye are OK to add.
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Re: R12 hoses with R134 Adapters

Postby wiztom » Sun Jun 10, 2018 11:47 am

Thank you for your response. I scrounged an adapter from my tool box. It allowed me to use the gauges one side at a time. I then used a hose from one of those Wal Mart charging kits to weigh, (using a scale), in Freon a little at a time. The AC is up and cold now.
I need two more of these adapter but cannot locate them on line and the auto parts guys just stare at me.

Thanks Again.

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Re: R12 hoses with R134 Adapters

Postby wiztom » Sun Jun 10, 2018 11:50 am

AC-3.jpg (173.19 KiB) Viewed 683 times
AC-2.jpg (207.39 KiB) Viewed 683 times
AC-1.jpg (171.5 KiB) Viewed 683 times

Sorry forgot to add photos
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Re: R12 hoses with R134 Adapters

Postby JohnHere » Mon Jun 11, 2018 1:14 pm

Tom, I'm trying to understand what the parts are in your first two photos (the ones with the Shrader valves), but I can't quite make them out. Your third photo shows an LP adapter (blue ferrule) that mates to an R134a LP port on the quick-connect side, and what looks to be a 1/4" SAE flare fitting on the hose-connection side.

If so, the LP (blue) hose from your R12 manifold gauge set should thread right up to the 1/4" flare fitting on the adapter. All you need then is one more of the same style adapter, except configured for the HP side (red ferrule), to which your HP (red) hose will thread in the same manner.

Doing this will eliminate any problems with the Shrader valves you mentioned earlier (assuming there are no Shraders in your hoses, either), and you should then be able to hook-up your R12 manifold gauge set directly to the vehicle's ports...LP and HP respectively.

Of course, Cusser is right. You could simply borrow an R134a manifold gauge set from AutoZone. Or, you could purchase a new set from this site's sponsor (Tim has a good one that he's offering), especially if you're planning on doing any additional work on vehicles that use R134a.

I normally don't recommend topping-off refrigerant because you never really know exactly how much you have in there, and you can't determine the correct charge from pressures. But if it's working well now, I think I would just leave it alone and tell your son to enjoy the "cool." However, if the system's performance diminishes again due to loss of refrigerant, then you'll have to find and repair the leak before evacuating and re-charging it.

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