Well i have a '93 f150 4x4 with a 5.8l and ac compressor i think is going out cause it ticks and when u cut it on it doesn't blow cold and on top of that when u get the rpms up it squeals. and i figured meh maybe it needs recharging and needs some oil... man what a headache i got into. Turns out my truck uses r-12 well a heads up i am clueless when it comes to ac. well i learned r-12 was pretty much outlawed and its hard to find and you have to have a license to buy it.. i know people who could buy it for me but still. so i went to a shop to get a estimate for a conversion done the right way. new accumulator. new fittings. and i gotta get a new compressor. and new orifice. labor will be 150 bucks. and parts and all will be 446.55 without ac compressor. and ill get a motorcraft ac compressor from Rockauto.com. is there anything im missing in a conversion? will it work just as well? will the ac compressor be made for r134a refrigerant? do i need to go out and just have the whole system redone? new lines? new condenser? new evaporator? any help and opinions will be much appreciated thanks everyone on FTE!

 

If I was you I would get a new system. R-134 has smaller molecules than R-12 so you would have a leaking problem with the old lines. If the seals are bad that could cause problems also. Not to mention R-134 uses PAG oil but R-12 used mineral oil.

A guy where I work (CAT, so we're all mechanically inclined) said they sell a kit that has some chemical or oil or something that basically you can run 134 in a 12 system. This chemical makes the oils compatible with eachother. You just need to make sure your compressor is good and you dont have leaks which a vacuum test could show. The kit costs like 50 bucks or so. He did this on his car and one of the other guys' older Corvettes so it does work. However, I do not know the name of it.

[edit] I found it. http://www.jcwhitney.com/r-134a-retr...D=3925582&cj=1

 

any parts store will have the conversion kit about $45. it works good, and will get you on the way quickly.
if you really want to go overboard, you could replace the orifice tube ($2) receiver drier, ($40) all the O-rings ($10) rent the suction pump, and replace the old oil with Esther oil ($10) and new 134-a ($30-40)

also most places will have the synthetic 134-a available, it is a bit colder.

 

I've used those conversion kits on a few different vehicles and they have always worked well. Walmart actually carries the kit for cheaper than you will get it at an auto parts store.

 

I would go ahead and replace the orifice tube. They are cheap and easy to do, and you will already have the system empty. The drier and o-rings would not be a bad idea either.

 

I converted my '89 over. Compressor was going out last summer, so I replaced it and drier(to get warranty you have to get both). I put in new orifice and charged it. Works okay, but surely not as cold as most vehicles I've had. Better then nothing. I also replaced the lines as they were 20 odd years old and looking a bit weak.

 

How well an R-134a conversion works and how long it will last is directly proportional to how much you spend. Just dropping in a few pounds of R-134a into an R-12 system without changing anything else won't get you very far in Texas, but maybe where you live you could get by with it, for a while, anyway. YMMV.

 

Thanks for all the input guys. The A/C compressor will have to be replaced. Im prolly gonna go all out and change the compressor, orifice, drier, and maybe have them check for leaks. i rather get it all done right all at once. cause i stay on the move constantly. I dont have the time to be trapped without a vehicle.

 

You will also need barrier hoses if you wanna keep the R134a inside the system over the long haul.

 

A mechanic friend of mine told me about a new R-12 replacement called Freeze 12. It is completely compatible with R-12 and the old oil. I used some in my '79 Thunderbird last year and it worked great. I'm thinking it was around $12 a can, so it is lots cheaper than R-12 or converting to R-134A.

 

you have to have a license to buy it. tried that already.

 

The freeze 12? That must be a state law then, because it is available "over the counter" here in good ole Missouri.

 

It depends on who you purchase it from. Obtaining an EPA 609 certificate is easy, it's an online test. I would recommend Freeze 12 over a R-134a conversion any day.

I have several of my vehicles running on R-406a, but I had a stash of it from another project several years ago.