73 RR AC Pump squeal

So... Last summer my dad had decided to accidentally overfill the AC compressor with 134A. It still turns, but when the AC is engaged it sounds like the belts are about to explode or something. Regardless, the AC blows out hot air anyway so its safe to assume I need a new pump anyway.

Thing is, while I was driving it last the car developed a horrible squeal. Not like a bad serpentine belt on a new car squeal, but a squeal just loud enough to be embarassing.

I am short on cash, so are these things rebuildable? Thoughts? Opinions?

Edit:
73 RR 400 HP 4bbl factory air

Thing is, while I was driving it last the car developed a horrible squeal. Not like a bad serpentine belt on a new car squeal, but a squeal just loud enough to be embarassing.

Remove or loosen the A/C drive belt. If the squeal stops then it's.......

A: the belt

B: The A/C compressor clutch trying to turn a "tight" compressor