Under chassis rust

[martinw]

The reason for the rust problem in this area is, I believe, due to it being the area that all water drains down to whenever it rains or you wash the car.

Remove the 2 rubber bungs close together (in first pic) if you have them, and wash the car (or just the roof/windscreen area) on a dry day and you will see where the water comes out from. Its the holes in that area.

Trouble is - the water doesn't fully drain away.

Having rubber bungs (if you have them) in those 2 holes doesn't help, but even if they are removed, the water still doesn't fully drain away. The bung holes are flanged which doesn't help. Maybe its the way the car sits, but the water seems to sit towards the rear and then starts rusting away at at any panels inside that void. 

Design problem ?!

I went through all this when I first bought my MC2 aerodeck and had rust starting in the same area as the first pics. Fortunately, believe I caught it in time. Removed loose rust inside, spray treated and resealed the whole void, treated and resealed exterior rust etc.

But if its gone too far - serious job - not just a single panel replacement, multiple ends of panels would have to be cut out, fabricated and welded back in, treated and sealed.

And this area is surely structural - with the number of panels meeting here, it's got to be - adding strength to the the whole suspension, subframe etc area.

BTW its not just a MC2 problem. My earlier MB3 with 32k miles had the same problem starting .... so check yours, whatever the model !