Pan rust

I had a couple spots on my pan that looked sketchy. I wire-brushed them with a power drill and painted the crap out of it with some POR-15. That was roughly two years ago now and it's still holding up. For what it's worth I painted a LOT with that stuff, frame welds, under body seams, anything I could reach with a brush really. Just be sure to clean/dry whatever you plan to paint as best as you can and don't get that stuff on your skin or you'll look like a dalmatian for a week...

POR-15 Gloss Black Paint Pint

I might suggest using a smaller, softer brush (brass bristles?) from harbor freight and brush the welds by hand if it's looking pretty bad. Loctite metal epoxy might do the trick for reinforcing the weakest areas before painting. I've seen online where people have used that stuff to repair cracks in the pan.

I dropped the spare and was able to get to a lot of trouble spots. I slathered the spare wheel chain with grease too in hopes of preventing it from seizing like on my old Toyota.

Anytime! Let us know if that works out well for you.