I changed the R-12 compressor due to a extremely noisey clutch bearing failure. The A?C worked perfect despite the noise. After installing a compatible Harrison 134A compressor, and the necessary retro fittings etc the system is not getting cold. The line from the condenser outlet is sweating? And the suction line to the compressor is not like it should. Pressures seem to be adequate. It seems like the orfice tube(assuming it has one) is plugging but the suction pressure is 30 or so psi. Not sure if I missed something on this model. I have changed several R-12 to 134A by simply evacuating and changing the freon and fittings only.
Flushing the system to remove the mineral oil and debris should be done.If you do not flush it at least replace the Accumulator/Drier a lot of the old system oil and trash will be in there it is cheap insurance it should be 20.00 - 25.00 bucks! Replace the O-tube it takes a ".072 Orifice white one" R134a and mineral oil do not work well together so leaving it in the system with R134a is recommened. There are many different suggestions when charging a R12 system with R134a. System must be evacuated before starting the charging procedure. I suggest you start with about 70 percent of the original R12 charge and add an ounce at a time until vent and pressure readings reach the best available results. Remember it is easy to over charge a system with R134a so patience is important
Let me know how it goes.
If I have helped positive feedback would be appreciated.