There is a jaw inside that broke on my 1984 300SD. I think it costs about $7 for the part. I had to temporarily repair mine once using a matchbook to wedge between the glass and the rubber weather strip. To get the door panel off you have to take off the door lock plunger, the latch plate, arm rest, plastic trim over the door latch, and I forget if I had to remove another screw from this...also the trim around the trailing edge of the back window must come off. Then push the door panel up; don't try to pry it straight back or you'll break off the plastic retainers. Good luck.