Belt slipping, that's one thing I need to work on, but for my alternator as I regularly go through deep water. Out east, Land Rovers get a lot of frame rust. the two options are waxoil, which wouldn't work well for body parts, and POR-15 paint, which does work well for body parts. It has a special primer, and the paint. It may only come in black though, but I have heard it stops rust. http://www.por15.com/ Powder coating works as long as no water gets past it. Once it does, the rust travels underneath the coating, unseen.
before powder coating get your parts acid dipped that would insure that there was NO RUST anywere on that part.