Old Compressor on new Gas

Dear All i would like to reimplement the aircondition system in my car. i have all original parts availabel. There is a question regarding the old Gas (12r)and the new 134a ( i think it was this number). The old original compressor also will support the new GAS it is only important to get the old GAS and oil out of the system and then it should also work well.

Many thanks for your ideas on this subject
crugone
Author: crugone