Air Conditioning issue 92 Deville

So I have a 92 cadillac deville that's still r12. The last charge held for a long time maybe a year or so. I am having a hard time seeing if there is a major leak I can locate. However, when I try to charge the r12 I jump the compressor and the compressor runs. Either it doesnt suck the freon in or it sucks air in from somewhere else and results in the pressure being too high to suck in any more freon. Long story short is that the freon in the cans is not getting sucked in. A couple questions. Is it possible for a compressor to run but not be working? I could have fried it by running it dry for so long. I have a long ride coming up and would love to have ac for the ride home. Anybody have any ideas on how I should proceed? It even seems as though that it's sucking in air from somewhere else because the pressure gets high enough to run the compressor without a jumper wire. But the compressor still sounds like it is running dry and then the freon can is still full. There is pressure in the hose from the can to the low pressure line