A few months ago there was a post about repairing rust on the bed above the wheels. I beleive someone said what to use on the rust but now I can't find the post. I am starting to have my paint bubble and some rust to appear right above the wheel well chrome strip. I want to repair it before it gets worse.

There is a product called Zero Rust that supposedly binds with the rust and stops the process. Can't vouch for it personally but the guys on the Bridge Crew for ODOT use it and swear by it. That is if it is just surface rust. If it is rusting through, that's another ball game.

For surface rust treatment use a phosphoric acid based product. The acid reacts with the steel and forms a layer of iron phosphate, which is usually gray to black in appearance, depending on the metal's content. The brown bridge stuff is the same thing just with a different metal formula in the bridge. Either way, the phosphate seals the metal from outside moisture and resultant iron oxide formation (rust).

If rusted through you need to cut out all the non solid metal. Then find a buddy with a sand blaster to whack what is left. Make sure you do the underside as well as the bed. Once you have the rust off, hit it with the phosphoric acid compound and let it dry. If the compound is one of the ones that has a soap in it, just hose off and let dry. You should have a black metal base left. Then bondo, braze or whatever you wish to get it finished.

If yo anually undercoat the box with wd40, that will keep a lot of rust formation from starting.....

Had to do on both my T's. Works.

If there is any layered rust get it off with a chisel or grinder (flap disk works nice and doesnt bite too hard.) You will find more wet rusty metal under each layer. If you are lucky you will get down to shiny pitted metal and it will not be too thin.

Use the acid on shiny metal as mentioned above and then rinse it and shoot with a high zinc primer. Coating with zinc is almost as good as galvanizing the metal. Maybe you can find a weld-thru zinc primer that is compatible with your paint: after all it is impossible to paint inside a spot welded joint.

I found that Eastwood rust encapsulator sticks to surface rust well but not shiny metal, pitted or not. They have a converter chemical pair too, the encapsulator by itself does nothing to the rust itself, it only seals it.

The 'rust converter' stuff in the spray can that turns surface rust black seems to work sometimes. It is holding up a year later in a place where I used it as primer and painted over.

I did this wrong a bunch of times before I started to get it right. Use your head and wear a respirator.

Thanks for all of the info. Since the paint is bubbling I am not sure what I will find underneath it. From what I am seeing, it looks like the wheel well sheet metal is bent along with the exterior bed sheet metal to form a lip. There is rust where the two are together and I am assuming moisture is getting in between there. I am planning to get the materials and start on it Labor day weekend.

dang .. I really want to build replacements .. but so far not yet .. http://www.toyotafiberglass.com

Here is a drawing in case you were wondering how the sides are put together.

I removed all of the rusted metal and it was worse than what I had expected. I will clean and coat the inside of the panels with zero rust and then fill with Bondo. Hopefuly this will last a couple of years. OK, what am I doing wrong? I tried to post a picture.
[img]http://www1.snapfish.com/slideshow/...72655/a=143063623_143063623/t_=143063623[/img][/image]

I was able to see the photo by copying the link. It looks like you took the metal off the outside fender skin and see part of the wheel well such as #65636A behind it. Welcome to Hell?

I went and looked at this part of the truck and it looks to me like this inside-wheel-well and the outer fender skin are spot welded to each other inside the flange that bends in around the lip there. This joint serves to hold the fender skin in place and increase its rigidity but I think you can live without a few inches of it.

You can patch the fender with fibreglass and build the surface with bondo but a lasting repair will require that you eliminate all the corrosion from the inner piece of metal too. Otherwise, the wheel well will continue to rust.

This is a lot of work, but I would consider to cut out the rusty inner wheel well and have a clean piece of galv steel welded in there (why not do the fender this way too if you are going to go this far...)

But you can probably do a decent job by removing what you can see/reach of the rust and treating the remainder with chemicals. Inside this cavity you really want to let your paint/chemicals dry well. I would not be opposed to a wax+oil cavity sealer like the one Eastwood sells in a spray can in this area before closing it up (watch for drains and dont clog them.)

If you are going to clean and undercoat the wheel well area (you don't have to remove all the old undercoat, just clean it and sand coarse) you can do a destructive test for rust with an icepick. Anything that punches thru must be removed. The pick will pierce the undercoating wherever you poke it, so you must clean the area and reapply it if you do this.

Don't forget to feather out an inch around the repair before you paint too.

About bondo: Bondo is to build surfaces, not fill voids. Bondo holds water like a sponge and promotes corrosion.

You are correct in what you are seeing eleet.
Thanks for the info, especially on the Bondo. I will probably go with the fiberglass for now and keep an eye on it. If it shows any signs of not holding up then I will go with sheet metal. Hopefully by then I will have some extra free time and more $$$$.

Since you were able to look at the pics, and if someone wants to post them the right way feel free to do it. Or let me know how and I will give it another try.