a/c retrofit adapter
 

I am trying to convert my r12 fittings over to r134 style fittings for an a/c recharge. The high side fitting threaded on just fine, but the low side adapter is slightly too big for the r12 fitting. I have gone to nearly every auto parts store in the area, and no one has any other size but the standard 7/16 low side adapter. Has anyone ever ran into this problem before?

The factory R-12 fittings should be 1/4" flare on the low side, and 3/16" flare on the high side.

Isn't 1/4" flare the same as 7/16" SAE? If so, that size is too big.

I believe so.

I've never heard of this problem. Something isn't right. Are you sure your low-side line is factory and has never been modified? Are the threads in good shape? Post a picture?

The first picture shows the fitting, the second picture shows how loose the adapter is on it. I bought the a/c lines from a forum member a few years ago, so as far as I know they are original.

There are two different size low side fittings for retrofit. I never bothered learning the actual fitting size always called them the big on or the little one. I have them on the shelf at work and I will try and check the number on the smaller one and let you know (Monday). It will be a NAPA Temp number but you should be able to cross it at another part store if you don't have a NAPA around.

Thanks there actually is a NAPA near me, I would greatly appreciate that.

Doing the same. The R134 fittings are much easier to work with. Still charging with ES-12 though. :)

from your picture it looks like you have the fittings backwards, the high side is the smaller hose.

DING DING DING DING! We have a winnar! The larger aluminum line is the low side, the small line that you posted the pics of is the high side.

Good thing Mazda used two different sized fittings...otherwise OP would've blown up a can of refrigerant trying to put a charge in on the high side.

The ES-12 master kit came with the red cap on the larger fitting. I have a manifold gauge set so I probably would have noticed the higher pressures. I really needed the other fitting so I can pull a vacuum and the manifold gauge set uses r134a fittings.

R-12 low side service ports are always 1/4" flare.

R-12 high side service ports can be either 1/4" flare or 3/16" flare.

You installed a <1/4" flare> to <R-134a high side> adapter on your low side line.

You need to hunt down a <3/16" flare> to <R-134a high side> adapter.

That is exactly what I needed to know! I switched the adapters and voila, the low side port is in fact 1/4" as well. The ES-12 master kit sent two 1/4" adapters one high side, and one low side.

I have since ordered this for the high side:

Charging Port Adapter Small 3 16" R12 Port to Accept R134a 'Quick Disconnect' | eBay


Thanks for all the help!

Well I see that you ordered it, but here is the NAPA numbers. It was the high side and not the low side I miss remembered. 409901 is the 3/16 and 409902 is the 1/4. The are like $5.29 a piece. 409903 is the low side for anyone wanting to convert...

Thanks I will save those part numbers for future conversions.