I was at a junkyard recently and one of the cars I took parts from was a 1983 300D. I remember leaning up against the "wall" right behind the back seat (back seat was gone) with my hand, and it flexed under my weight. I just put my hand on it, and it was even close to the door were I put my hand, so I would assume that it would be more solid there, close to it's attachment to the rest of the car. Barely any of my weight was on it. All of the times I've had the back seat out of my 1980 300D, it always seemed pretty solid, and I don't think it would flex if I leaned on it.

Does anyone know if there is a difference between years with regards to this wall, e.g.- more solid/less solid. The only thing I could think of that might cause that was that the 1983 car didn't have the fuel tank anymore, which is right behind that wall. But still, it seems like, if I remember correctly, that my 1980 still felt like the metal was more solid.