I posted about this last fall but I've got more info now. I have a 69 f100/f250 with an under the dash ac unit. This unit is labeled "cust-o-matic" by glandy or glardy or clardy I can't read the letters exactly. Under the hood is an eaton compressor marked M 744027 F2101-20030 08-78 it also says refigerant 12 on the tag. There is no sight glass next to radiator as someone suggested last fall. On one of the hoses coming off of the compressor is a fitting that a refill hose for r 134 refrigerant fits. I see no tags anywhere saying it was converted but I was told that the old r-12 used different fittings to refill and this must have been converted. I figured I would come to you guys for a second opinion. The ac works but needs topped off as it is not very cold. Thanks alot, Mike

 

Most likely it's been converted to R134a. R12 can still be had but the price is astronomical. You might want to check a couple shops near you to see if anyone has a refrigerant analyzer. A quick check can tell you for sure what's in the system.

 

If it's been converted, then it should have adapters screwed onto the fittings. Aluminum rings that make the fittings larger then orginal R12.

 

Mike, Don't know if it would be helpful on your info quest, but I believe that compressor is a York style rather Eaton, but you can verify that too.

At this stage of the game, I might suggest swapping out everything to the newer Sanden rotary compressor with 134A and be done with it.

Those old Yorks use a lot of engine power and mpgs to run.



John

 

I went to the garage to look at it again. There are 2 fittings coming off of the compressor, near the top is a tee fitting that that looks like a 90* elbow with threads cut into the back side. The hose from that goes to the firewall. The fitting for filling the system is screwed into the threads on the back of the ell. The slip coupling on my can of r-134 fits this fitting. The other hose comes out lower down and goes towards the radiator.
The tag on the compressor says eaton. It looks like a very small old style air compressor. As for replacing the whole system, welllll theres the new Easter dress and new summer clothes and shoes to match for my little girl, and tires for the wifes car well you get the idea. Thanks alot Mike

 

i planned on using 134a, bought the fittings, then changed my mind and kept it r12. but still have the fittings on it because thats what fits the low and high pressure gauges that i have for it. (and its all stealthy i can tell people its 134a). if i ever sold it to someone and didnt tell em theyd be in the same situation as you. fact of the matter is the only way to tell for 100% sure is with a device that can tell the difference. heck it could even have some death potion "freeze 12" in it for all you know.

 

Do have it checked. A few years back there was a guy around here that was using propane. It would cool ok but one of the cars sprang a leak created a heck of a mess, luckily propane stinks. My point is folks use goofy stuff some times so if your not sure have it checked.

 

Ammonia is another gas that shows up in " witches brew " R12 substitutes. At one time ammonia was used in refrigeraters. There are still folks out there who know how to service ammonia systems but like anything else you have to know what you're dealing with first.