Yotarunner, The last owner changed the oil and refrigerant and put the fitting adapters on the compressor. It cooled, but not very well in the AZ heat. The R12 is ice cold.
The adapters for the gauges were a pain because there isn't enough room to get the larger R134 gauge connecters on. Had to grind the case just to get one on.
I've done a ton of conversions myself on Cat equipment and it worked well, but we changed the drier, and expansion valve or orifice tube depending on the system.
Who knows what was done when mine was converted. Maybe too much oil or other problems. If nobody chimes in, I may just flush my system, get a compressor, drier, and expansion valve. It's all original stuff with 420K on it.
Thanks for your advice.