You seem to have found a good solution. Plus clarified the location a little more.(was not where I thought) One of my 123s seems to have had water in the trunk. Probably is leaking rear rubber window seal I imagine. Created rust in the trunk and lower rear portion of wheel well. If that turns out to be the case I will put small drain hole in well until I locate and repair the leak. I just find leaks by spreading newspaper in area and using garden hose if not obvious. Guess will have to hold off on my 500.00 offer for your rusty old car now. Excuse the lengths of my posts. Did not want to get into argument with hattersguy as already have one wife. (FYI benzboy 8 is offering carfaxes on a thread just a few above yours)