[lupo]

This is a tough area to deal with. With any welded seam strip the paint and soak it good with a phosphoric acid rust remover that contains zinc.. Weld your pieces and if need be and you have the equipment and skill if you use a permanent rust sealer use the silver formula not the black. For those of you that do not have welding equipment you can use Allmetal body filler for pinholes or the extreme permanent rust sealer that's is pretty thick