I'm trying to do a major rust overhaul on my XJ. The more I tear it apart, the more I find unfortunately. How would I go about repairing these rusted spots on my fenders and rockers? Obviously, I can't just slap it with converter and paint it. I want to actually fit the root issue. I don't want to have more rust growing under the paint in another year or so. Can I cut the big stuff off, grind it dow



n, and apply bondo? The fender part is tough because it is also where I mount the under-fender and the fender flare. I have never done any of this so bear with me. Any tips help.

 

If you want to fix it properly there is only one way to do it. Cut out all of the rusted metal and weld in new metal.

 

Rust can be killed dead by converting it from iron oxide to iron phosphate (the Black Oxide finish you see on impact sockets) by using Ospho or Rust Mort.
Follow the firections to the letter. Period.

Before priming and painting remove absorbed atmospheric moisture from the metals surface by either warming to 120°F for two hours or rinsing with 100% strength isopropyl alcohol.
Apply primer or sealer within 45 minutes of completing the drying cycle or repeat it. In humid environments cut that 45 minutes in half.

Then coat with primers, paints, sealers. In rust prone areas further protect the painted metal with corrosion prevention compounds.

 

Awesome, thanks for the responses. Very helpful.

 

I am working on fixing similar rust issues on my XJ. If you don't want to do everything all over again in a few years, you have to fix it right. Rust converter does work for light rust areas, but not for stuff like this. It can't make rust into good metal.
You will need to cut ALL the rust out. Then make or buy pieces to weld in. Classic2Current fabrication makes pretty much all the xj rust repair panels you could need. Well made and a good price. https://www.c2cfabrication.com/