Door question

Door sags come from worn hinge pins or their operating bushings. As such you can test for it by opening the door to the near closed position and trying to move it up and down. If the door moves and feels like it is hitting a stop on the top and bottom then the pins are worn and need to be replaced. Sagging hinges are very common and quite some work to correct.

Another thing to check is the inner door skin relative to the weatherstrip that seals the door. It is critical to fit door skins to the car. Too big and they touch the molding causing closing issues and too small and they show a visible paint line from the inside. Perhaps some of the beading on the edge has moved causing extra resistance so go in there and look for rub points.

Lastly, close the door very slowly and check for latch pin alignment. If the door generates stick in the last bit of travel then your latch may be a little out of alignment. This is easily solved by loosening the 4 screws that hold the latch to the door jamb just enough that it can slide a bit so that it can 'self-align' with a door closing or two. After a few openings and closings you can re-tighten the screws. Of course make sure that both the pins and latches are well lubricated as this contributes a lot to a smooth door.

On the subject of the latch on the jamb, this is a Mercedes part and if it operated a long time out of alignment the cone can be worn and affect your door closure. Luckily these parts are cheap and you do not want the OEM Mercedes part as it has the three pointed star on it. Buy a quality aftermarket part as it is exactly the same but does not carry the star stamping on it making it a perfect replacement.

Hope this helps.