You should charge refrigerant gas (can upright) into the low side (only) with the engine running at about 1,800 RPM, the A/C on, and the blower on medium speed. The low-side handwheel on the manifold gauge set must be open and the high-side handwheel must be closed. With the engine and A/C off, the ...

I'm assuming it's a full-size Chevy pickup. If so, the specs I have list 26 ounces of R-134a and 8 ounces of PAG 46. When you say it took "some" refrigerant, how much exactly and how are you trying to charging it...small cans or 30-pound cylinder? By weight or by pressures only? Are your r...

It's possible that your manifold gauge hook-ups aren't depressing the port's Shrader valves, which will prevent refrigerant from entering the system. If you have the type of connectors with the small blue and red thumb-wheels, ensure that they're rotated all the way CLOCKWISE after connecting them t...

With an R-12 system, steady foaming and bubbling in the sight glass suggest that it's still a bit low on refrigerant. A full charge typically shows a mostly clear sight glass.

If you decide to add some refrigerant, don't forget to purge the yellow (center) hose of air at the manifold gauge set. Otherwise, you'll be introducing air into the system (albeit a small amount) along with the refrigerant, which of course you don't want.

New o-rings, that is.

Looking real good. Put a shop-vac nozzle up to the ports to suck out any debris that might have gotten in there. I'd also apply a little Nylog to those o-rings just before re-assembly, and you should be all set. I hope there are no leaks anyplace else.

Of particular interest, I found the following information from Chemours (below), which is a spin-off company created from the DuPont performance chemicals business. Recently, Chemours adopted Freon™, the old DuPont trademark for R-12, to represent all of the company's HFC products, including R-134a,...

Don't forget that you can replace just the clutch assembly. You don't have to replace the entire compressor, which is probably still in good working condition.

I don't recommend introducing unknown alternative refrigerants into a system when pure R134a is readily available. As Cusser asks, why bother? Besides, you could wind up doing more harm than good. Higher operating pressures, flammability, unknown country of origin...heck, I'd just avoid using the st...