the floor on my 76 ford f100 is rusted through , you can only tell from under the truck since it has a vinyl floor cover. what is the best way to fix it?

 

The best way is to cut out all the rusty stuff and weld in new metal. That's what I did on mine. My brother is a "tanky" so he basically fabricated and welded it all for me. We just took some thicker sheetmetal (couldn't tell you what gauge), and after all the rusty stuff was cut out, he welded pieces back in. Made most of the cuts straight, even though rust was crooked, just to make our job easier. Even if I show you were we did it, it is hard to tell. Besides that, it's all either under the carpet or under the truck with undercoating all over it. No need to buy repair panels, IMO, unless you are talking about body panels such as rear wheel arches or something else that is more critical.

JJ

 

Here is what I did: I carefully cut back to good metal and then sanded the floor inside the cab and under the cab. I then painted on a rust convertor/ protector. I allowed tihs to dry for a day or two.

I bought several packages of fiberglas matting--the heavy stuff, not the cloth-- and the resin/hardener. I carefully cut patches and then applied the resin/hardener to the cloth and then dtretched it over the hoels, careful feathering the edges. I overlapped the metal about two inches. I put three layers on the inside and thenwent under the cab and put three more layers. Itis surprisinng how fast this stuff sets up.

When it had cured for a day or two, I coated with rubberized undercoating on the inside and out, then reinstalled the insulation and vinlyl florr pads. It has held up well and shows no signs of deteriorating.

 

My experience with a '76 F150. If you have some floor rust that you can see, there's probably more. Pull the seat by removing 6 bolts (three each side of the truck) and get a friend to help get the seat out. If the middle seat belt strap is keeping you from getting the seat out, DON'T CUT IT! Just let it dangle out the door for now. You're in luck if the original vinyl flooring is still intact. I had to remove the trim at the rocker panel to get under my vinyl floor. Set the vinyl and underlayment aside and take a good look at the cab floor. You may have to remove the rubber door seal to be sure you've got a good view of everything.

It was at this point that I checked out the local VoTech for adult evening classes, got signed up, and started to work. The shop had all the equipment for me to use AND a great instructor to help out when I got stuck. I cut out the rusted area, installed replacement front cab mounts, cut sheet metal to fit the areas in question, welded them in place with some help from shop friends, cleaned up the entire cab floor of surface rust primed the entire floor inside and out. You can decide for yourself whether you want to paint the cab floor to match the cab or be content with primer and replace the vinyl and underlayment along with the seat. All depends if your repairs are to make like new or to pass inspection and get it back on the road.