AC Rebuild on 1990 200

[Al Powell]

Friends, last week the AC compressor grenaded on my 200 while driving back 
from a long trip (5 hours crossing Wyoming at 102 degrees with no AC at 80 
MPH makes the ears ring from having windows open, dontchaknow).  I'm sure 
it's the compressor because cooling disappeared, the compressor sounds like a 
box of rocks being shaken, and the clutch on the compressor is shedding bits 
of rubber from the resistance it's encountering in turning the compressor.

To save time on the job, I'm having a local shop vacuum the R-12 out of the 
system, remove the compressor and dryer, then flush the system.  I'll take it 
from there, replace parts, then have the system re-charged.

Any comments from those who've BTDT about staying with R-12 vs. converting to 
R-134A?  I've converted a Chevy pickup to R-134A and the system worked fine. 
 However,  with the @30% cooling efficiency loss which comes with R-134, 
cooling was nil at idle, but good when moving with traffic.  This is not what 
I want with the Audi, which is the family car.

Also, any comments about how thorough one needs to be with changing seals, 
O-rings, etc. when converting?  I didn't go through the seals when converting 
the Chevy, but that's not an Audi...with all its perversity. personally I'm 
inclined to think that the system doesn't have to be gone through, as small 
leaks could be tolerated and R-134A is cheap.  However, Audis don't have a 
"top off" function - the AC needs to be discharged before being re-charged. 
 I don't need to get into frequent system re-charges.

Instinct tells me to keep the system the way it was designed and stay with 
R-12, but I'm open to discussion from those who've tried it.  Replies 
directly to me are encouraged.

Also - I'm checking parts sources for compressor, clutch and dryer.  I will 
check Blaufergnugen and Linda at Carlsen - anyone else have great sources 
they want to suggest?

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Al Powell
Fort Collins, CO
powellae at home.com
cougfan1 at gocougs.wsu.edu
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