Battery Well Corrosion Nightmare

[Mikebear79]

Man, this car is turning into a can of worms every time I turn around. I purchased some POR-15 today to get some tiny rust spots within the rear doors and one small spot next to the right exhaust header that I figured was caused by excessive heat peeling the paint away over time. I quickly remembered that there may be some corrosion around the battery tray area, so after removing the washer reservoir and the battery, I was literally sick to my stomach. On what is otherwise a very clean CA/AZ car, the acid from the batteries over the years had eaten holes through the tray and the space beneath the tray was full of corrosion and debris. Why why why would Mercedes put a bunch of wiring down there? It's like a rat's nest of old corroded wiring running all over the place. I'm assuming since I'm pretty sure everything works in my car that the wires aren't totally as messed up as they look. But still, what a mess. What do I do? POR-15 the crap out of everything? What about the nuts and bolts and small pieces like that? I guess I should replace that bushing underneath the plastic cover too while things are apart. I'm wondering if the small rust I am seeing next to the exhaust header is actually coming from the other side where the ****show is. Pics included...