I had a busted check strap in my beemer (also does the detent thing) and it interfered in a big way with proper function. Fortunately, the passenger and driver side part is interchangeble, so I was able to get a lightly worn passenger side strap at de bone yard.
You've almost certainly heard by now that the MB door panels come off in and upwardly fashion as opposed to most cars that just pop straight out.
BTW, I'm not going to faint at your feint of an MB question.
