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OK, so on my 80k mile 1993 F150, I'm starting to get a little concerned about creeping cab corner rust (see pics)...any ideas on how this can be nipped in the bud? Inside the truck under the carpet is fine, just concerned about what is shown in the pics.
First remove then re-seal the third brake light/cargo light, that's where a lot of leaks are found. Then remove the plastic trim inside to allow access to the bad spot, clean that as best you can with a wire brush, then spray one of the many brands of rust stop paints on it. Clean the outside the same way. but put some filler (bondo) in the holes, if any, then smooth that over and paint the area with more rust stop paint. Not primer, PAINT. Paint sheds water, primer does not.
Check inside the cab corners, Ford did spray some foam sound deading crap in those areas which hold water causing rust. I removed that junk from my 89 F250 and it was not fun. Then do what others have said to do.
Yes, get rid of the foam at corners.
Also, bad sealant in the gutters will let tons of H2o in to the cab.
I use Prep and Etch from Home Depot to convert rust prior to painting and it works great.
And at less than $20 per gallon, it goes a long way. https://www.homedepot.com/p/Klean-St...0220/100406369
Yes, get rid of the foam at corners.
Also, bad sealant in the gutters will let tons of H2o in to the cab.
I use Prep and Etch from Home Depot to convert rust prior to painting and it works great.
And at less than $20 per gallon, it goes a long way. https://www.homedepot.com/p/Klean-St...0220/100406369
I got a rattle can of the Locktite brand rust converter and didn't use all of it, like you say it goes a long way.
Step 1. Wire wheel the rust and remove any detritus or debris.
Step 2. Apply rust reformer such as phosphoric acid or Evapo-rust
Step 3. Paint at least 2 coats or POR-15 or equivalent inside and underneath corner. Light coats are imperative. You may use regular paint on outside.
Step 4. Most important; Find the cause of the rust & fix. Re-apply body seam sealer around cab corner seams, reseal third-brake light and drip rail/rain gutters.
Step 5. Spray Fluid-Film inside and underneath cab corner.
Step 1. Wire wheel the rust and remove any detritus or debris.
Step 2. Apply rust reformer such as phosphoric acid or Evapo-rust
Step 3. Paint at least 2 coats or POR-15 or equivalent inside and underneath corner. Light coats are imperative. You may use regular paint on outside.
Step 4. Most important; Find the cause of the rust & fix. Re-apply body seam sealer around cab corner seams, reseal third-brake light and drip rail/rain gutters.
Step 5. Spray Fluid-Film inside and underneath cab corner.
Step 6. Take her off the road in winter and drive a littler beater.
As others have suggested, that sound deadening foam Ford used in all the corners - high and low - is just evil. It's especially difficult to get out in the forward corners where it's between the sheet metal in places. I tried removing it everywhere I could and then treat the metal with Phosphoric Acid, rinse, and then hit it with a rust encapsulator primer such as nomorerust.com.
As others have suggested, that sound deadening foam Ford used in all the corners - high and low - is just evil. It's especially difficult to get out in the forward corners where it's between the sheet metal in places. I tried removing it everywhere I could and then treat the metal with Phosphoric Acid, rinse, and then hit it with a rust encapsulator primer such as nomorerust.com.
I did not find any of that foam, maybe some one before me removed it.
My 89 F250 had bunch of that foam to dig out of the cab corners. A 88 F150 I stripped for parts did not have it, but the corners were rusted out badly. Not sure of the 91 F150 I have, got to check that out.
