Good deal, Richard! Glad it will be running for your long drive. I know it would be a miserable drive without it. My '60 a/c ran great for the 3.5 hour drive between Ft. Wayne and Dearborn last week. We have become quite spoiled, I think, accustomed to having a/c in all our vehicles. In its infancy, a/c was a luxury, both in homes and vehicles. Things have a way of going full circle, as there was a time that a/c repair was pretty routine, but new EPA laws since the early '90's have changed all that. We're back to having a/c be a luxury, as your wallet well knows!
Personally and professionally, I think the EPA totally mishandled the entire problem. Assuming that R-12 is as "dangerous" as the EPA claims, we deal with dangerous chemicals all the time in this world. The answer comes with proper containment and handling, rather than completely replacing the chemical itself.
When vehicle air conditioning first appeared, the components were basically industrial grade, installed into a moving vehicle. Components such as an actual expansion valve were replaced by cheap expansion tubes. Hose assemblies were cheapened too, going from barbed fittings that can be reused with new rubber hose (R-12 only, R-134 requires Parflex) to crimped fittings that have no barbs beneath them, and easily subject to leakage. The list of component cheapening is almost endless. The workhorse GM A6 compressor (axial piston movement, 6 cylinders), such as your '73 has, was replaced around '78 with the pure crap R4 (radial piston movement, like the old airplane engines, only 4 cylinders) made primarily of aluminum. The A6 had its own oil pump and sump, just like a car engine. That's what the bulge is on the bottom of this compressor. The R4 has no such oil supply, but depends on the refrigeration oil to constantly travel through the system for lubrication. As soon as there is any restriction in the cheapo expansion tube, the oil flow stops, the R4 starts to self destruct. I can't tell you how many of these I've replaced for people over the years, and I kept a container of plugged, yukky, expansion tubes, as evidence.
Cars of the '60's and earlier '70's had suction throttling valves, regulating evaporator pressure so that they would get nice and cold, but not cold enough to freeze the condensing water vapor that was passing over the fins. Blah-blah-blah.... the list of cheapening to saved a penny during manufacture goes on and on, and of course continues to this day. I apologize for getting on my soapbox about this, but as a lover of old cars and true American ingenuity and engineering, the changes I've seen leave me very disheartened, especially with the short sightedness of the government that totally mishandles a situation.
On the good side is the fact that so many beautiful and wonderful old vehicles still exist and are lovingly maintained and exhibited. I smile when I see a raised hood and a nice OEM air conditioning system stands out. I know yours has been changed, Richard, so please don't take that as a personal slam. You did what you had to do.
I'm hoping that the former owner of your Lifeliner, Dave McCamey, will be able to visit us a bit during Hudson. Dave and I were good friends in earlier years, and it's incredibly sad to think how some thugs changed his life forever. Tom