First off the rusting of the bed wheel wells. What really causes this? I've heard anything from stuff just sitting on the lips to a foam strip used in newer trucks to prevent vibrations.

I'm dealing with is the 86?-97 obs style beds. I repaired my truck with fiberglass/bondo/por15 5 years ago and it's still holding up. I've also been spraying diesel/drain oil under my truck since then.

Also about 5 years ago after I saw the rust first appear I found a clean rust free box that needed a decent dent/crease pulled along the the lower front. The bed came off a old 1989 f-250 that was used on a farm to haul hay around... I don't think this truck ever left the property. But the bed was painted once. Before I bought it I went around with magnet/knife and checked for weld seems, bondo... I even scratched the paint off in places that looked funny and resprayed it. I just seems the truck was white and they tried to fix the dent at one point and painted with with black enamel.

Non the less this bed has been sitting in my field for 5 years and no rust has yet to appear. So I think it's solid. Now I found a guy who paints all of our trucks at work and he's willing to paint and do the bodywork on it for me in his free time. He' hasent seen the dent but he thinks he can reshape it. I bought the replacement panel for the area awhile back.

I live in NJ but I never drive this truck during the winter unless it rains and drys and there's no signs of salt/salt residue. Heres a pic below of the bed. You can see how messed up the lower section is and also pinholes up more where bondo was used.

So back on topic once I finally get this done and back on my truck what's the best possible way to protect it? What actually causes the rust to happen in this area? I've hear people drilling drain holes? But where? The inner fender? I honesty dont see how water/dirt gets in between them. But when I cut open my current bed a lot. I mean a lot of dirt came out.. Would spraying gear oil/bar oil between those two be a smart idea?



That picture was from the summer. (notice the lower section and the body filler used above it?
Here is a picture back from when I went to first look at it.



For you body guys out there. How would you approach fixing this? Theres just minor dents around the best. Drivers side is perfect.