I use this procedure on my 84 300SD

The door panel is rather easy to remove, just do it CAREFUL and SLOWLY :

Remove the two screws at the handle remove the two screws and the metal piece at the door lock pull out the the light beneath the door now the panel should be free (that is : I might have forgotten a screw or two)

Now for the exciting part : The panel is pushed gently UPWARDS, dont pull out ! it usually helps to tap at the bottom of the panel, again upwards.


There are plastic hooks on the doorpanel which grab the door. These are the ones that break if you are too eager. (They can be glued back on again)
Try to preserve the vapor barrier