Make sure you have good hoses still, They don't last forever. I used to work in a A/C shop that did aftermarket installs and custom stuff for hot rods and we had machines and tools to redo A/C lines and hoses. You would be surprised how many we did in a day for outsiders. I would change them anyway if I was going to use R12, just because the stuff is expensive. I'm thinking you probably have a orfice tube type of system not a TXV type as someone else suggested, I would check it if you indeed have that system. TXV systems are fairly new I doubt they were using them back then, Alot of Domestic's use the orfice still on new models. Just some thoughts....rue
