Thanks, guys. This car is nice enough to be worth a quality repair and, if I buy it, I want to know what I should do. Assuming the system maintains integrity [doesn't leak materially] for a number of years, I would be inclined to leave the R-12 in place. At least the controls seem to work: blower speed, etc. I read once that this design may be the finest M-B has ever built, and, after driving this car: 11 years and 150K miles old, and comparing it to my previous experience with a nearly-new car, I know this is possibly a true statement. thanks again; I will let you know if I make the deal.