My front driver regulator broke at one of the mounting points. It cracked at the casting where it mounts and would not roll up properly or stay up all the way. I have a donor door with a regulator in it that I am going to swap. The front ones are a completely different regulator setup than the rear. The front have a gear driven type and the rear are of a cable lift design. The rear regulators are pretty easy to swap out. I don't know about the front. I have swapped several regulators in other cars and it usaully take three to four hands at a time. A helpful source of information on this repair is in the HAYNES 190 manual. Good luck.

__________________
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T