I tried both 134 and r12. I just made a filling hose by cutting the r12 hose and splicing on the 134 hose. Left it in for a while with poor results, not that cold. I did a full evacuation with a heat source on the dryer while vacuuming the system for several hours. I filled the system with about 1 1/2 cans of R12, which by the way can be easily bought on Ebay with nothing more than an Ebay account. Just search R12, you will see what I mean. I also walked into an auto parts store while in Tennessee a few years back and asked about R12. The counter person produced a case of the small cans and asked how many I wanted at about $20.00 each. It is very easy to get, not real cheap, but it works in my Buds Benz system incredibly well. I have been using that fill of R12 for about 3 years now and it will freeze you out of the car. I have not been impressed with any modern car using the 134 stuff except for a rental Hyundai compared to older R12 systems. It is just not as cold.
My Buds Benz system is from the mid eighty's I believe. I have the records, but I know it was meant to have R12. It was in the car when I purchased it.
A strange thing happened after pulling the vacuum and filling the system with expensive R12, I spotted a tiny leak on the accumulator [dryer]. It was next to a small brass plug. I was very upset, I knew all my R12 was on it's way to Al Gores nostrils. I grabbed my soldering gun in desperation. I sat there about an hour dabbing solder and flux on that leak while under pressure. I miraculously got the solder to take and it has held ever since.
Now for my thread Hijack, I need a mount for my accumulator. It is just flopping around under the hood. I need a mount like the one used on an ignition coil because of where it needs to mount. Any ideas?