The ratchet function is engaging, and I have not checked the cable for tightness and the back brake assembly, it is definitely on my agenda now. I forgot to mention that the roll back and forth in the parking gear does not always occur. There are a few times when I get to my driveway and I put the car in parking and it doesn't roll back at all, but most of the time it does and it doesn't seem to me that having owned other automobiles that it is a normal roll back or forward distance, unless my model mercedes was originally known for that far rolling. Remember all this has nothing to do with the parking brake working, or not. I just don't use the parking brake beacuse it does not work. The reason to have the parking brake working from the beginning was to stop the car from rolling so much when in park mode.