>I had my R12 AC recharged last week by a local shop.  Asked about converting
>to R134 and he said they had done 240 conversions over the past years.
>Unfortunately he said they'd re-converted fully 90 of them back to R-12
>because of failure.  Some problem with the oil and even when they used the
>very best, they still had problems with leaks etc.  They don't do them
>anymore.  I know nothing more than this, maybe their quacks but they do have
>a good reputation in town.  Hope it works for you, I'm interested in
>everyone's successes after 6 months or a year.
>
>Jim
>91 Syncro AW

They're not doing a careful enough job of inspecting and repairing the
systems then. 90 out of 240 is a huge amount! When I did this, we never had
to convert any systems back, although we did occasionally have failures,
but these were ultimately traceable to undetected deficiencies in the
system, i.e. almost worn out compressors, contamination, etc.

Keep in mind that conversions are typically done when the system is broken,
often with a seized up compressor. A seized compressor can often spray bits
of metal through the system, causing repeated failures. Also, 10 year old
ac systems usually have a lot of worn out or marginal parts, such as hoses,
compressors, etc.

Joshua Van Tol -- jjvantol@uswest.net