Has anyone determined for fact that the AC system is low? If it is low, or empty, then double check the main hose for fatigue. You mentioned the PS pump was leaking, I imagine that a good portion of that fluid may have saturated the main hose.

I noticed you mentioned that the AC system failure was sudden. My thoughts would be to double check the harness connection at the AC compressor. The 3 wire harness leading from the chassis was known to be short on the 124 body. The engine shifts when you accelerate and over time the individual copper strands inside each wire would break.

There is little question that at some point you may/will need to replace the Evaporator as it is prone to failure but wouldn’t it be nice to repair three broken wires…………..