Advice on rusty floorpan

ratio411

Founding Member
Apr 21, 2002
3,870
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Pensacola FL
3 of 4 of my floor pan sections are good...
I have the passenger rear section getting pretty advanced though.
How would you folks handle this?

I have wire brushed the area and gotten all the lose stuff.
The biggest hole is probably about the size of a dime.
There are alot of little pin holes.
Can I wire brush the area more and weld up the holes?
If so, what would I put on the metal afterwards to protect it and maybe even stop the rust from coming back soon?
I don't think it is far enough gone to warrant a new pan, the bottom looks perfect, the top is where the damage is because of the carpet holding moisture.
Thanks
Dave
 
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No picture to go off here but I wouldnt weld up these holes you speak of because where all that rust was use to be good metal that turned to rust and now that youve wire wheeled that old rusted metal away your left with thinner metal that when welded will more than likely make bigger holes,

Id determine how extensive the pin holes and other rust is and maybe try welding in a patch of the bad area after you cut it out, this would keep u from having to replace a "whole" panel Or you can purchase that part of the pan and cut out what you need to match it exactly


this is just my opinion, besides im rust paranoid I cut out both full floor pans and back sections and replaced them on my Coupe :nice:
 
ratio411 said:
3 of 4 of my floor pan sections are good...
I have the passenger rear section getting pretty advanced though.
How would you folks handle this?

I have wire brushed the area and gotten all the lose stuff.
The biggest hole is probably about the size of a dime.
There are alot of little pin holes.
Can I wire brush the area more and weld up the holes?
If so, what would I put on the metal afterwards to protect it and maybe even stop the rust from coming back soon?
I don't think it is far enough gone to warrant a new pan, the bottom looks perfect, the top is where the damage is because of the carpet holding moisture.
Thanks
Dave

the floor pans are cheap money, why screw around trying to fix it? I'd buy the pan, cut out all the bad places and decide if you want to replace the whole thing or just a portion of it.
 
The whole area has been thinned with rust.
It is only through in a few places though.
I appreciate your opinion, but if I bought an entire pan section, it would be just as easy to weld it in rather than patch.
I still haven't convinced myself it is that far gone yet.

Any other suggestions?
Dave
 
Here is a suggestion that I got from the guys at Mustangs Plus. I have never tried it, but it just might work. They said that they do it all the time for non-concours cars.

1. Clean all of the rust off of the old floorpan and get it down to bare metal.
2. Prime it with POR-15 or a comparable rustproofer
3. Lay a new floorpan section over the top of it and weld it into place. Do not cut out the old one. This just gives you that much more metal before you have to do this again.
4. Put seam sealer around all of the edges.
 
Interesting...

I suppose if I use a power brush and shaved the pan down to super thin, non-rust...
a new pan would lay right in.
I will think hard about that.
The car is definately not concours.
It is a restomod, with far more mod than resto.
Thanks
Dave
 
TobyGaff said:
Here is a suggestion that I got from the guys at Mustangs Plus. I have never tried it, but it just might work. They said that they do it all the time for non-concours cars.

1. Clean all of the rust off of the old floorpan and get it down to bare metal.
2. Prime it with POR-15 or a comparable rustproofer
3. Lay a new floorpan section over the top of it and weld it into place. Do not cut out the old one. This just gives you that much more metal before you have to do this again.
4. Put seam sealer around all of the edges.

Hey that method is just so wrong man! :notnice:
ALWAYS cut the rusty part out before welding a new one in!
 
TobyGaff said:
Here is a suggestion that I got from the guys at Mustangs Plus. I have never tried it, but it just might work. They said that they do it all the time for non-concours cars.

1. Clean all of the rust off of the old floorpan and get it down to bare metal.
2. Prime it with POR-15 or a comparable rustproofer
3. Lay a new floorpan section over the top of it and weld it into place. Do not cut out the old one. This just gives you that much more metal before you have to do this again.
4. Put seam sealer around all of the edges.

I think that is the worst Idea I have ever heard. Metal over metal is always a bad idea, look around your rusty cars, most rust starts in metal over metal area's.
 
I agree, not a good idea, it adds weight too. You may as well replace the pan. If you want to patch it, cut out the rust until the edge of the cuts have original thickness metal, and put patches in. It's probably easier and almost as cheap to just cut out a big section and put a new pan in though.
 
Well, like I said, I have never tried it. I have always cut out the bad spots and patched them right. I was just presenting an option that they said they have had great success with.

The reason that most rust starts in metal over metal areas is because there is not primer or paint between the metal. In this case they suggest priming the pieces before you put them together to eliminate that problem.

Not a great idea, just an alternative that I am passing on. Do with it what you want.
 
If you have all the rust out and the biggest hole is a dime size, it sounds like an excellent candidate for a POR15 trunk kit. They also sell PORPatch which is a putty and works well (I fixed some non-visible holes in my trucks core support with it.)

http://www.prp-porstore.com/page/por15/PROD/Kits/FPK

Alternatively, if you can get it to work:

http://www.por15.com/subcat.asp?id=35

Stuff is expensive, but I have had great luck with it on several items. Should be substantially less invasive than welding/cutting
 
Cut out the bad and replace with new, if you want a permanent fix with any resemblence of quality to it. If quality and looks are not a consideration and you just intend to keep the soles of your shoes off the pavement, pop rivet galvanized sheet metal over the bad. How ever you eventually decide to repair or disguise the problem won't matter if you don't repair what the cause of the problem is in the first place. I would imagine you need to check the cowl vent for the source of your floor rot problem. If that is the case, and you don't fix it, you are going to get good at floor repairs in the future!