I have a 76 Mercedes 300D. I got it 3 summers ago and when I got it, the air did not work. The previous owner said it had worked in the recent past. My brother in law is a mechanic. We discussed whether I should spend the money for R12 or not. He was afraid it would leak out quickly and I would have wasted my money. I bought a 134 kit at Wal Mart. We used his shop vacuum pump and then the kit filler hose setup. So far so good. I have had working AC for 2 summers now. We did not change out any other components. Don't know how long it will last but so far so good.

Randy