Scaling rust spot problem on undercarriage of my vehicle

[NH73]

I always felt after 100,000 miles, the undercarriage of my vehicle looked pretty good, abet some surface rust here and there. 6 months ago, I found a spot behind the front driver wheel to be scaling. So I sprayed with Berkebile PFE 2+2(similar to Fluid Film), hoping to prolong the spread and going deeper. Today I was disheartened to find an area was scaling yet. Didn't spread but knocked off scaling. I knocked off some big chunks of scaling and sprayed more of that PFE 2+2 on. So here is my question. Is that area doomed, no matter what I do? Is it possible that those large chunks were forming 6 months ago and the PFE 2+2 could not penetrate to stop it?

 

[doitmyself]

Your scenario is a possibility - the product did not penetrate. Is it possible that the rust is coming from the inside and working it's way out? I find that this "inside out" rust to be a much worse problem than surface rust. Spraying the inside of all panels/parts is equally (maybe more) important vs. a topical undercoating protection.

It might be better to use a low viscosity rust reformer first, followed by an oily type rust proofer to both sides of the area?

Best of luck with this. Rust sucks. Attempting to slow it down is better than nothing.

 

[AutoMechanic]

I have a car that’s from up north it has a little rust spot in the frame what I done was got some rust transformer that makes it a paintable service so I sprayed undercoating on it and it has done great since. So I recommend doing that.

 

[NH73]

Your scenario is a possibility - the product did not penetrate. Is it possible that the rust is coming from the inside and working it's way out? I find that this "inside out" rust to be a much worse problem than surface rust. Spraying the inside of all panels/parts is equally (maybe more) important vs. a topical undercoating protection.

It might be better to use a low viscosity rust reformer first, followed by an oily type rust proofer to both sides of the area?

Best of luck with this. Rust sucks. Attempting to slow it down is better than nothing.

Much the rust is on a body support than on the floor board. I can't see the inside of the support. But I guessing the way it is rusting, it is not inside out. But I could be wrong. If I lose, I think I could find someone to cut it out and fix it.

 

[Yah-Tah-Hey]

Try Eastwood anti-corrosion aerosol spray. Leaves a waxy coating. Black or amber.

 

[mattd]

Unfortunately the only way to truly stop it is to cut it out and weld in good metal. Everything else is shoveling **** against the tide once the rot sets in.

 

[nascarnation]

I'm a big fan of WoolWax. Plus it smells good. Wish I had it 40 yrs ago when I lived in NE Ohio.