AC R134 Conversion (Page 8/8) RWDPLZ JUN 14, 11:36 PM Check the system pressure first with a gauge set, you don't want a face full of refrigerant. If it's empty, and you haven't installed any of the new parts yet, it doesn't really matter, worst case the residual oil is absorbing water in the old condenser, old accumulator and/or old undercar lines. Once you re-install the hose assembly, you can vacuum it down to remove air and boil off any moisture that may have been introduced. It would also a good time to pull and check the old orifice tube to check for bits of old compressor. Just hold off on installing any of the new parts until you're ready to replace everything including the o-rings and vacuum it down to check for leaks, if the car is going to be sitting a while before it's running, you want it to be holding vacuum. You can't add refrigerant until the engine is running. computer_engineer JUN 21, 12:28 AM quote Originally posted by RWDPLZ: Check the system pressure first with a gauge set, you don't want a face full of refrigerant. If it's empty, and you haven't installed any of the new parts yet, it doesn't really matter, worst case the residual oil is absorbing water in the old condenser, old accumulator and/or old undercar lines. Once you re-install the hose assembly, you can vacuum it down to remove air and boil off any moisture that may have been introduced. It would also a good time to pull and check the old orifice tube to check for bits of old compressor. Just hold off on installing any of the new parts until you're ready to replace everything including the o-rings and vacuum it down to check for leaks, if the car is going to be sitting a while before it's running, you want it to be holding vacuum. You can't add refrigerant until the engine is running. Well, There is still pressure in the system. In a way, I suppose that is good news - no major leaks. Maybe just a slight leak on a schrader valve or an O-ring. There is still a small amount of R-12 and R-134 left in the system, but the car doesn't run, so I can't take it anywhere to have it evacuated. But I have to put the new compressor in place, replace the dryer, condenser, orifice tube, and the O-Rings. The only way to replace the compressor, is with the engine tilted with the cradle. So I will need to crack open the system, unfortunately the refrigerant will get "accidentally" released. Do you have a recommended schrader valve to replace the ones on the low and high side ports? RWDPLZ JUN 21, 05:30 PM I doubt any shop would recover it with known contaminated/mixed refrigerant, anyway. The new conversion fittings listed in the parts list come with new valves, see Spadesluck's first reply to this thread, under 'Valve Cores' computer_engineer JUN 27, 05:27 PM quote Originally posted by RWDPLZ: I doubt any shop would recover it with known contaminated/mixed refrigerant, anyway. The new conversion fittings listed in the parts list come with new valves, see Spadesluck's first reply to this thread, under 'Valve Cores' I would also like to put a new schrader in the high-side port as well. Do I need a certain part number for this one, or are the high and low side schrader valves the same? Also, I assume that anything from 4 Seasons would be okay, and stay away from anything cheap or from the auto supply stores??? Thanks.