I have a 1992 formula that was converted to R134a before I bought it. A/C ran great and cold. However, the compressor took a dump about 2 weeks ago. You could feel the vibration when it engaged in the seats.

Now I have another compressor from a 1991 formula (my race car) that I recently took out and was in good shape, but was using R-12.

What do I need to do (if anything) to replace the bad compressor in my r134a system with a compressor that came from an R-12 system?

 

The usual: Remove the drier & orifice tube; flush the entire system; replace the drier & orifice tube with new ones; evacuate, oil, and charge.

 

Is it normal practive to replace the dryer when replacing the compressor? Since the system is r134a, and the compressor is not, is there a special wat to clean the compressor?

 

It's normal practice to replace the drier.

Use an oil that is compatible with both the R12 oil and R134a oil. Otherwise, no other issues.

If the original conversion was done properly, the o-rings should have been replaced with green ones (forget the material off the top of my head, but I can get that for you if you need it).

 

Thanks for the info. I'll call ACDelco, really just to rule out the oils bad for this application.

 

Pretty sure it's PAG 150 oil for that setup now. If the old compressor got chewed up some inside the system probably does need cleaned, new drier and exp. tube, and a good evacuation (vacuum) before recharging.

 

Next question, should I perform a flush of the system, different from a vacuum, to get out all the old oil?

 

that's up to you. You should if your old compressor gernaded and sent stuff through the system.. check the orifice tube for shavings in it.

Some or a lot of manufacturers require a flush..i believe rockauto will require proof of purchase of a flush kit if you need to warranty a compressor.