72 F100 Floor pan rust - replace or patch

[Knuckled]

I've started the process of breaking down the interior of my 72 F100 bump and getting it ready for priming painting. The floor pan has some heavy pitting and a few see thru spots. I'm looking for recommends on whether I should replace the pan. Or, suggestions on how to treat the pitting and holes especially around the ribs in the metal. I put up some pictures to get an idea. Cheers!

[67mann]

It's beyond repair...no amount of rust treatments is gonna save that. How is your cab mount underneath it If it's good get yourself a repop pan and patch in the bad section. Be sure to rust treat the inside of your cab mount when you get it open

P.S. This is a very common repair for these trucks.....so ask away if your not sure how to go about it......there's plenty of us that have done it

[Ranchero50]

Your ISP is in Washington State, I'd opt for replacement panels and only use what you needed. A torch will find the limits of the really thin metal quickly, just run it across the rusted areas and the too weak sections will flash melt away giving you an indication of what you need to replace. I wouldn't replace more than needed (IE swap in the whole pan).

[Knuckled]

Thanks for the reply, I may be a little naive in asking but is floor pan partial (or full) replacement possible w/o taking the cab off? The truck is my daily driver.

[Kurt Combs]

You can do it with the cab on the truck. I did one side in my 72 in about five hours, but I butt weld all my joints and the fitting was the hardest part of the job. The welding doesn't take long. Make sure to protect your dash and all glass in the cab from splatter. I forgot one window on the other side of the cab and it still has little black spots were the splatter burned into the glass. You might do a search and see if anyone has previously posted pictures of the process. Oh, and remember to look underneath before you start cutting to see what you might accidentally damage.

Just a thought, has anyone used adhesive to glue an overlapping panel in place? I'm thinking pop rivets and glue. Stuff is expensive and you don't have much time to mess around positioning parts, but it is strong and would seal the joint from future rust.

[Knuckled]

Thanks for the guidance, I will post my progress and let you all know how it goes.