Out of all of the fox/tbirds we've had in the immediate family, they've always gotten the rust around the rear window, which in the end resulted in water in the trunk area. I've taken a wire brush to the areas I could see, and hit it with Ospho (Sp?) to turn the stuff into black iron. I've not painted it over yet because I wanted some input.
Is there any way to keep that from happening, or progressing further (to non ospho'd areas) It's the one problem none of us ever figured out how to negate.