Hey guys, I have a 1977 Ford LTD with the 302 in it and the AC hasn't been working in many years. I had to drive back from work in 91 degree weather with near 100% humidity, and it about killed me to drive in that (and we're not even into July yet). I can't afford to buy another car right now because even a decent used car is going for like 15k all the way to 40k. I would like to know what it would take to get the AC working again. I noticed that there was no belt connected to the compressor, and I spun the compressor by hand and it moved freely (don't know if that detail matters). I desperately need my AC working again and I have no clue how the AC system works. I really appreciate anyone who answers.
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When you spun the compressor did you actually turn the compressor crank, or just the clutch?
There are a huge number of things that could be wrong with that 45-year-old AC system and it would need to be converted over to R134a refrigerant if that has not been done in the past. (For starters all the old refrigerant has likely leaked out.)
The AC hasn't been run in many many years, so I assume it has not been converted. I've been studying on this, and from what I've heard, you're required to put a new sticker somewhere stating that it has been converted to R134a. Also there would be new fittings on the AC lines, so I will check that out soon.
Edit: I spun the part where the belt pully is. I'm not sure if the clutch was engaged or not.
Probably it has not been converted, but sometimes people do it themselves and don't bother with the sticker or new fittings.
It sounds like you just spun the pulley. With the AC off the clutch would not be engaged. You have to either energize the clutch, or turn the front clutch plate, to actually spin the compressor.
Servicing that unit will require charging with R-12, the original Freon. That is a highly controlled substance by the EPA today (the CFCs were blamed for the hole in the ozone layer). I'm not sure if it's even accessible to professionals anymore. With any luck, your system may already have been converted to R-134a, which replaced R-12.
Manifold gauges for an R-134a system will hook up to the high and low sides if it has been converted. You would want to see at least if the system can hold a vacuum, if it has been converted. If not, there's a hole in the system. @chucktobias knows a lot more about converted systems than I do.
Realistically if you don't know how AC works and don't have a friend available to show you the ropes you need to have an air conditioning specialist evaluate what needs to be done. Try to find a shop with some graybeards working there who know those older AC systems. If you're very lucky it just might need to have new seals installed and be converted to R134a. (I have a car older than that with working AC that still has nearly all its factory original parts.)
Do not take it to a dealer or a chain shop like Pep Boys or Firestone.
Here are some sites that may help you get an idea of what's available and what's involved:
https://www.classicautoair.com/retrofitting-r12-r134a-classic-auto-air/
https://www.youtube.com/watch?v=__alchrw7CE
https://www.youtube.com/watch?v=B1VG1OHEfAM
