i've only worked on 1 mb with a clutch and that was a 126. manuals on a benz are pretty rare. but, based on my experience with bmws and hydraulic clutches, when the pedal sticks to the floor either it needs new master and slave cylinders-probably your case because of the age-or the new master has not been bled enough and still has air in it. bleed it and cross your fingers but i'm betting your cylinders are just tired. replace both, a new master will overpower an old slave in a matter of days, if not with the first push. good luck, chuck.