134 has larger fittings than r-12, and thanks "tilt" it is so illegal to dump freon to the atmosphere, $10,000.00 fine from epa if caught, granted it's hard to get caught but still. and over charging is a serious prob. to the extent of blowing lines and or comp. sounds like you did a good job but you did have some luck as well. i'm ase certified and still scared of a/c, if not cooling properly it could benefit to recharge the system, if a newer car there probably would be a leak or a compenent prob. but on early to mid 90's it's probably about time for a freshun up! and on the cost of the retro fit from 12-134, you are advised to change receiver dryer, o-rings, and freon, most shops will charge you to recover oil freon and pull a vac. on system, this would be the reason for the high charge, i would still shop around though, as your friend could be getting the shaft