I was under my 2002 today and had the usual rust issues, broken bolts. Most of my rust is on the rear axle and some of the brackets, the frame is in pretty good shape with most of the rust at the welds.

My question is what is the best product to touch up and protect the frame as I work? I want to be able to clean and prep and area and then protect it in small sections without doing the whole under carriage. I am thinking POR15 but it seems pretty labor intensive. I have also heard good things about Monstaliner.

On a related topic, should I replace bolt with stainless or just regular, fresh bolts? A friend of questionable knowledge said stainless was the way to go and worth the extra money but another said they aren't necessary if I replace every few years.

Stainless likes to gall, so you would want to use anti-seize everywhere you use a stainless bolt. The OEM bolts are (generally) very good quality and have integrated washers or flange heads that look good and work well. Now that I'm thinking about it, anti-seize every bolt/nut that doesn't need/use threadlocker. You'll thank yourself next time you are working on that part.

Why not just use Fluid Film or similar on the undercarriage to keep the rust at bay? Also, remember the frame generally rusts from the inside, out - most treatments won't get the inside of the frame...

-Charlie

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-Charlie

+1 on the fluid film. I did some surface rust removal on the outside of the frame with a wire wheel and flap disc then painted with Eastwood rust encapsulator. Used some rust converter in the spots that were worse before painting. I had to patch a 3" x 14" section on the passenger side near the muffler as well. After that I used the Eastwood internal frame coating to do the inside of the frame rails and cross members.
Eastwood Internal Frame Anti-Rust Coating, 14 oz. Spray