A/C repair and conversion to R134a

[carmangary]

Two questions:

My A/C currently doesn't work. The compressor is hard and rough to turn. Maybe a bad bearing. Are these things repairable with common tools or do I need special pullers, etc? Are junk yard A/C compressors worth messing with? There are plenty of those to be had. There is one junkyard that offers a $4 warranty on parts so maybe that is an option? What are your thoughts?

Next, what do I need to convert to R134a? I bought a vacuum pump and guage set from harbor freight so I have that part now. I know I need to change some seals and parts but not sure which ones. I looked on some websites but the information varies.

First thing I want to do is try to pull a vacuum on the systems and see if it leaks. There is currently no freon in the system. Hopefully it leaked out through the bad compressor and not from the condensor or somewhere else.

 

[megaladon6]

don't bother with trying to change parts of a compressor, it's not worth it, just change the whole unit. compressor's don't like being left sitting around, so unless the junker has a sealed/working system it's a big gamble to get a used unit.
to do the changeover just but the kit. they have a valve that screws on over your original ones. all you need to do is remove the original stems, put the new valve bodies in place, vac the system to 30inHg, let it sit for 30min in vac, charge your oil/dye, charge your freon to vehicle specs, and run.
i'd do the compressor first, then pull vac. if the compressor is leaking it can mask any other leaks so you'd just go in circles. plus it's very hard to find vacuum leaks. find a small thing of AC dye and put it in with the oil. run the system with a minimum of freon and use a black light to look for leaks. (you should do a black light check before doing anything in case there was dye previously and to make sure everything is clean.)

 

[billyjack]

IMO a bad compressor isn't worth messing with. I might take a chance on a junkyard unit if there was still pressure in the system and everything spun freely. Otherwise it's off to the parts store. I did the conversion two years ago on my Camino. Doing some web searching, I found an old Car Craft Magazine article and this link from a DeLorean site: http://www.dmcnews.com/Techsection/r134.html. I completely disassembled the system, flushed the compressor with mineral spirits, let it drain for a week and blew everything out with compressed air over and over again. I then reassembled the system with a new stock accumulator and orifice tube, blue or green O-rings and ester oil in the compressor. Pumped it down for over an hour and fed in the R134. Couldn't get enough pressure in the system with cans, so I went to a shop and had it charged with a jug. Been working fine for two summers. The hardest part of the deal was finding an old-time parts store that had all the proper o-rings. I've seen the "quickie" conversions done without disassembling the system. Just pump it down and add some oil additive and R134. Sometimes it works, but more often it does not. If you already have to disassemble the system to replace the compressor, might as well do it right. Hope this helps.
Bill

 

[carmangary]

Bill, sounds like you did it the right way. I will probably follow your footsteps. I am going to try to take apart my old compressor just to see if I can. If I can't get it apart I'll just buy a new one I guess. I have some time to save up for one before hot weather comes again. 🙂

 

[jeff0547]

A friend wrote an article a number of years ago about converting from
R-12 to R-134. Here is that article, hope it helps:

http://www.buickperformance.com/ac.htm