I went to my local MB dealer to get a replacement mast because mine was kinked a bit in the solid wire part and would not retract fully. The parts guy brought out two choices, one as indicated by the patrs book, and the other matching my sample. Both were obviuosly toothed, and mine was sort of smooth, but we figured the teeth might have been worn off. I took the one that matched my sample, and installed it. The mast still wouldn't retract fully, so I figurd that thend of the nylon pigtail was broken off inside the take-up reel. I dis-assembled the motor box and thoroughly cleaned everything(no broken pigtail was to be found) , put it all back together, and it still won't retrac t fully ; about 8" sticks up. After thinking it over for a while, I cut about 4" off the tail ,and tried again. This time, about 3 3/4" stuck up, so I cut 3 5/8" off and tried again. Now it retracts fully, but the motor runs for about 1/2---3/4 of a second after the mast bottoms out. Do I need to adjust the cam/micro-switch to prevent motor damage? ('78 300D)