I think you may have fallen into the issue of varying push rod lengths (for the master cylinder). I'm not sure that this has ever been fully resolved, but basically MB made at least two different versions of master / slave clutch cylinders for the 123 240D, and if you mix / match then trouble will ensue. Add in aftermarket parts, and you have a recipe for frustration.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC