If that is a Nippondenso compressor, the seal is an easy replacement, can be done with the compressor in the car if there is room for the tools.

Evaporator is a HUGE pain in the W124 chassis, probably as bad or worse in later models.

I've done one in the W124, took me three days.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!