Old Chrysler AC retrofit

["Warren R Anderson" <wranderson@xxxx>]

Any o-ring that you change must be compatible with PAG oil which is the oil
to use with R-134A. Use mineral oil or special AC o-ring lube only to
install. Your compressor might have some rubber in it that would not be
compatible with PAG/R-134A. Maybe there will be other input. Hoses should be
OK.

Your type of compressor will live longer on mineral oil. Check the sump per
your manual. Some reman compressors will come with a full system charge in
the compressor and this must be adjusted as mineral oil will not mix and
migrate properly with R-134A. PAG is put in the receiver/drier for system
lubrication which is your expansion valve and EPR valve. You do need to get
as much mineral oil out of your system as possible as the stuff will settle
and it takes up volume.

Refrigerant charge level will be about 80% of R-12 factory level. You will
see bubbles in the sight glass with R-134A. Full charging will send high
side pressures sky high.

There are flushing fluids available although I can supply no recommended
names. Straight compressed air is not acceptable (especially with R-134A;
can go boom).

R-134A systems use fittings of different size than R-12 and adaptors are
readily available.

With regards to IMHO, I do not do retrofitting; at least not yet. R-12 is
readily available. R-12 outperforms ANY other refrigerant ever used in a
mobile AC system. There were some retro kits available from the OE's for
some late model vehicles and these kits will most likely include increased
capacity condensers and recalibrated expansion valves (or orifice tubes as
req'd) and even condenser booster fans. The people we work for want good
working AC and a retro system in any configuration will not satisfy me or
the people I work for. R-134A is attractive only because it is cheaper than
R-12. A PROPER retrofit to R-134A will be more costly than fixing and
recharging an original R-12 system on R-12. When the industry runs out of
R-12, our shop will be prepared to retrofit as required because we are on
top of the latest developments. So far, R-12 is the best performing
refrigerant for mobile use. The most glaring fault apparent with R-12 is
that it is banned in Boston.

Mike; This is a deep subject with a lot of twists and turns and places where
you can make some serious judgmental errors. I spend a lot of time on the
phone with non customers on many subjects and would be willing to do so for
you. My son is the one that spends the most time with our internet group
concerning all matters of tech issues and he would be happy also to share
with you the knowledge and experience of many techs (and us as relates to
acceptable parts sources in AZ) that have been there and done that all
across the US. The full picture is more than I want to spend the time
relating over the internet.

Warren Anderson
Sedona,AZ