I received an adequate conversion from R12 to R134 about 3 years ago. I'm in SO CA so perhaps the lower efficiency was not as much a factor as perhaps in Texas or the South East. The condensor and fan remained stock.

Considering Charlie's car is 20 years old, (like mine) I would have serious reservations about whether the hose fittings are leaking. I'd pay an A/C guy to sniff out any leaks with one of those leak detectors. Goes off like a Geiger counter when looking for stray freon. That way you'd get a good idea what is leaking and what needs service. At minimum the seals on the compressor are most likely suspect and a new compressor is on the list. The hose o-rings should be replaced. But Larry is right, this will cost you some money to do "right" correctly.

We could start a whole other thread "is it getting any cooler these days?"

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)