Reply to "air conditioning"

If its within the budget the R134A conversion is money well spent, but it requires replacement of most of the stuff Steve mentioned. Steve is OK, he wants your car to work well.

The R134A molecule is smaller and far more corrosive than the R12 molecule. It will leak out between the molecules of the R12 hoses. The R134A hoses are known as barrier hoses, and have a lining within them (usually Teflon) to contain the R134A molecule and to prevent the R134A from damaging the rubber hose material. The R134A gas will attack the rubber parts designed for the R12 gas system (i.e. the compressor shaft seal, standard hose material, and even the O-rings used for the fittings). Its not compatible with the lubricant used for R12 either.

Since the hoses, rubber parts and lubricants compatible with R12 are not compatible with R134A, they "should" be changed. That includes rubber compressor parts. You can keep the stock evap and avoid pulling the dash apart; but the expansion valve should be replaced for one designed for the characteristics of 134A. Steve's modified evap increases the evaps cooling capacity to make up for the differences between R12 and R134A. If you don't mind tearing the dash apart, that's a good mod too.

Scott Bell (ZR1 Pantera) has experience with this conversion and with Steve's evap.