Homemade A/C Lines

["R. Cummings" <cumm@flash.net>]

I have not done a conversion on an Audi. With my coupe I was always
concerned that the head pressure was marginally high with R12 and would be
worse with R134a. However, someone recently mentioned on the list that they
had had their system converted to R134a and it worked fine. In that same
note they said the York compressor was being replaced with a Sanden.

The York, (now CCI) is very robust but is big, ugly, noisey etc. etc. My
Coupe still has R12 but the next time it needs service I will convert it to
R134a.

To do that you need to recover the refrigerant, fix any leaks, replace the
receiver/dryer, use R134a "O" rings at any connections you open, drain the
oil from the compressor (you don't need to flush, just drain it). Install
R134a fittings on the high and low service ports. If you car does not have a
high pressure compressor cut out switch, this needs to be added. Add an
ester based oil charge, then evacuate and charge with an amount of R134a
equal to the R12 charge less 10%. Add a sticker showing that the system has
been converted and the amount and type of oil and refrigerant. You can do
everything yourself except recovery of the old refrigerant and charging with
the new (assuming your not certified). Good luck.