Originally Posted by Beagle

A couple of possibilities...

1)About 6 months ago I received a phone call from a friend with a 123 300D. He was stranded with no clutch and described the symptoms exactly as you did. I towed him home and pulled the tranny when I'd established it was nothing external. What I found amazed me. The slave push rod had worn right thro' the release lever leaving a clean 8mm hole! The push rod has a 10mmŲ collar about 15mm from the dome end which caught in the hole but now not enough travel to release clutch though it felt normal. I welded a small piece of gauge plate over the hole and hardened it (the original lever is case hardened) - he's had no problem since.

2) I pulled the tranny on my own car to replace an oil seal some time back - lucky I did! The release bearing had just about worn right through the pressure plate springs leaving a cluster of thin razor sharp fingers - another week or so and it would have pushed right through. There were no symptoms or warning this was about to happen. The incorrect release Brg. had been fitted - should have been the later self-centering type. There are 2 or 3 different pressure plate/release brg. combination's(at least).

There is some good news if this is the case. The Sachs pressure plate from MB agent is,for some obscure reason, unbelievably cheap +/-$80! The Clutch plate on the other hand, around $250.