I haven't had problems with rusting screws, but I do know that Stainless Steel screws are not supposed to rust. My boat has many Stainless Steel screws and they have not rusted. However, some Stainless Steel is of low quality, i.e. made in China, and thus is less pure steel with more iron left in. It is the Iron content that will rust. Just my $.02.

T Alan B -- you'll find rusty screws (evidence of water intrusion) in many places on your RV (unfortunately). What Cate&Rob taught me (years ago now) was to coat replacement screws with silicone sealant prior to reinstalling new ones. I've also experimented with wrapping screw threads with the white (silicone) plumbing tape. The point is to provide a seal that prevents water intrusion.

For replacements, I go to the local Ace Hardware with the old one in hand and find a stainless steel version. Usually they are a #8. The originals may be self-tapping, but I go with standard screws. If the original hole is messed up and won't accept the #8 there are a number of strategies to rectify the problem.

A fantastic website with more information about fasteners is at boltdepot.com.

Howard