Ok, my 1980 Buick's air conditioning doesn't work and I might like to use it a little bit. I'm sure it's a matter of dried seals and rotted soft parts from disuse...the car sat unused for years. I had it charged maybe 5 years ago and it worked for that summer but I'd rather not keep leaking refrigerant.
Where do I begin? I imagine there are some common failures I should work on before even considering pressure testing and getting it charged.
Maybe you can take an easily accessible joint loose and inspect the o-ring there. If it is cracked, then all of the o-rings will likely need to be replaced.
If that o-ring looks good, then unfortunately it might be the compressor seals...
It is too bad that there isn't a mix of cheap gas and dye that could be put in a system to easily check where the leak is...
Some people say that all of the o-rings need to be replaced when converting to R132, but I had good luck on my 94 Nissan 240, with just using a R12 to R132 retrofit kit (which was just a fill valve adapter). I have to add 1 can every 2 years and I feel that is an acceptable rate of loss.
#1. take all the fittings apart, and replace the O rings with new ones. Buy the green ones, they are compatible with newer refrigerants. It doesn't hurt to slop a little thread locker on them before putting it back together. Guaranteed it won't leak unless you have a leak in a physical component.
After that is done, hook it to a vacuum pump and bring it down, then see if it maintains the vacuum. If it does then you have no leaks, Charge it up. I recommend one of the R-12 replacements such as "Freeze 12" in your car. You will not get satisfactory performance out of R-134A in that vehicle. Freeze 12 is a mix of 134A and Propane, and it gets insanely cold, works better than R-12 ever did.
When you want to troubleshoot any old ac unit, a few steps are mandatory. A common cause of an ac unit not functioning is due to the accumulation of mold in the evaporator core. Possibly, a hose may also have gone loose. You should get your ac service done after regular periods to ensure its smooth operation