R12 to R134a conversion

[CarZombie 25]

My A/C compressor has gone out. I have a 1970 Mustang convertible with factory A/C. Engine is a 351C. I believe I have the York compressor. Somewhere down the line it developed a leak in one of the compressor seals and it is now making a grinding noise when the A/C clutch is engaged. The system has R-12 in it. My A/C mechanic said when the new compressor is installed the system needs to be switched to R-134a.

I would like opinions and information on the pros and cons of the following: Can and should I just get a remanufactured York compressor, evacuate the system, install the replacement compressor, replace the drier, and refill with the R-134a. This is what the AC mechanic is saying he would do. However, I have read some reports that R-134a will destroy the seals in an R-12 system over time, and the expansion valve needs to be replaced. Of course I have read other reports that say, just do it (as outline above) and you will be fine. Any real life experiences out there?

As I see it, my other option is to go to a Sanden A/C compressor conversion kit with the R134a. I understand these are a lighter weight compressor and supposedly give you better mileage with the A/C on. That would be nice as my current A/C costs me about 1 to 2 MPG when it is running. Has some one done this conversion? Is it worth the extra money? Does it look right for the car? Again, any real life experiences out there?

Thanks much and please add any other thoughts you have on this.

[68stang289 26]

I had my first 68's A/C converted over to R-134a and I never had a problem. R-12 is illegal now so unless you have a can of it laying around, you won't find any shop that will use R-12. Not to mention if you can find it, you're looking at like $50/pound last I heard (and that was awhile ago). So your choices are either to go R-134a, or not have an A/C.

 

I unfortunately can't help with the compressor questions.

[jag 10]

Another alternative is to use Freeze 12. I do not have experience with this, but you just put it in like R12. Do a search and decide whether you would go this route.

JAG

[danno 128]

It is my understanding that the gaskets from a R12 system must be replaced to be able to use R134 in it. If this is not done, the R134 will leak out in about 2 weeks. R134 will also not get as cold as R12, another thing to consider. So on a real hot day, it might not work as well as you would want. Any shop will not be able to recharge it with R12, but they can completely evacuate the new system and allow you to put it in yourself. I bought some last year for $20 a can. It takes about 2 and a half cans to fill the system.

[68stang289 26]

I never had an issue with mine when I converted over and the gaskets/seals were not replaced. I had the car for about a year with the R-134a conversion and never had an issue. I also had a 1984 Porsche 944 that I switched over to 134 and drove for 2 1/2 years after that without a single issue. Again, no seals or gaskets replaced. That has just been my experiences though and I may have gotten lucky.

 

I do 100% agree with the 134 not cooling as well though.