Converting a R-12, York compressor F210R based system to 134. 1986 Mercedes 280 G-Wagen. It was operating GREAT until something punctured the condensor (in repair right now). I plan to:
- Flush all lines, condensor and evaporator
- R&R all O-rings with correct material o-rings
- Draw a deep vacuum using a Yellow Jacket 4cfm for a long time. I'll be using a "real" set of gauges.
- Use Poly Alpha oil http://www.rocoil.com/rocoil2.html (ROC AA1 ISO Viscosity Grade 68) from AC Source http://www.acsource.com/cgi-bin/SoftCart.exe/scstore/shophome.html?L+scstore+potf2348+990934939
- New receiver/dryer
- New York (CCI) compressor (the old one had leaky seals so its headed for new seals and my 1981 Volvo (different head plate though))
- I've read just about everything I can get my hands on on this subject. But I'm still listening

Questions:
- If the performance is not acceptable with 134 and I want to return to R12, will I need to flush out the Poly Alpha? From what I can determine the answer is no?
- Where is a really good ambient Temp to pressure table for 134?
- I've read that 75% of the R-12 weight is a good place to start. Any differing opinions.
- I've seen some technical discussion regarding the oil viscosity and amount. PolyAlpha is a darn light synthetic oil at ISO 68 so that is good. Yorks operate at a wide varity of oil levels, 6 to 16 ounces per their operating manual, but in those discussions I noted that several were saying the too much oil can markedly reduce heat transfer efficiency. Any suggestions from you all on the number of ounces?
- Does anybody know where I can have a RCVR/Dryer cut open and have the newer desiccant installed. The price of a new R/D for a G-Wagen is 10 times the nominal charge.

THANKS EVERYBODY!!!