I would find some Stainless bolts with fender washers if possible. If not get the best you can find of the right diameter. Washers on both sides and you should be fine. If you wanted to take an extra step you could always put a dab of the red RTV sealant under the washers as well, but I'm not sure that is necessary. Good for you, I need to do the same thing on my 4D.