1995 F250 RCLB 4x4 5-speed, 165,000 miles, mostly stock. Rust in all the usual places for a midwest truck (fenders, bed wheel wells, core support, etc), but then we stumbled on this:

That's the inside of the C-section of the frame, left side, looking forward, at the rear spring perch. Those are the fuel and brake lines, and the midship fuel tank is off to the right. A view you'd never see unless you took the truck apart. I just jammed the camera in there and shot blind. The bump is one of those ingenious Ford rivets holding the spring perch.

The inside surface is delaminating, but in what feel/look like pretty deep layers. A couple of crops below give a little better perspective of the depth.

Soooo..... how bad is this? Is it unsafe to drive? How much, if any, does it compromise the frame structure? Ideas about how to get it down to clean metal, and then what to do with it? We're thinking pull the bed, drop the tank, disco the lines and wires to get clear access. I know POR-15 is the "done thing", but it's bat-$#!+ expensive and NAAAAWWSTY to work with; we just got a couple gallons of Fluid Film, and were gonna see what it can do, along with Rust-oleum.

We have some waste ATF, and have heard that it's even better than engine oil for this kind of stuff. Would it be worth soaking the area in ATF _before_ any permanent coating?

What about welding it? There's always that concern that when you weld/layer metal, you just create a space for more rust to occur. And then there's the concern of the effect of welding on the original metal strength.

Unfortunately it spends most of its life on a gravel/dirt (too much dirt, not enough gravel) driveway.

So will a frame with this much delamination survive?

 

Can you get at it to drill a hole and see how bad it is all the way through?

 

Well, I could drill through from the outside, but I'd have to be darn careful about those fuel and brake lines. I don't think I'd want to try that on that lower area, but the one up higher I might be able to do that.

 

Maybe some Rust Doctor or Rust Killer would slow down the damage on the rest of the frame and undercarriage.

 

I'd try and determine for sure how bad it was then go from there. If its bad enough and you tow heavy or haul heavy loads often it may need some repair. If its not real bad maybe you could do like Pete said and clean it up and at least try to slow down the rusting.

Hi Pete.

 

I'd start with your original idea of pulling the bed. A twisted wire brush on a grinder will expose just how bad it is and make your decision easier. Do not fear welding, but cut out the bad portions and replace with new metal, not plate over it. I wouldn't soak anything with ATF you plan on painting. Phosphoric acid will do a fine job of converting the rust to iron phosphate, a paintable inert substance.

 

X2^^^^^^^^ then maybe try some of this.http://semproducts.com/product-catal...n/rust-shield/ I got some to paint the frame of my crew cab. I haven't used it yet, but a buddy that does paint/body work uses it all the time, he says it's really good stuff. I paid like $72 for a gallon of it. That's about half what POR 15 costs.

 

IMO if you cut out a portion of the frame and put in new, grind the edge of the frame and new frame piece, to allow a "v" type of weld, weld in place, and diamond plate both sides of it. That is if its that bad. Probably should just pull the bed and inspect like these guys said.

 

Yes, just being able to weld and knowing the proper way to weld are two different things. One thing about having an open vs box frame, is you can get to both sides.