After a successful crossmember transplant, engine rebuild and sealed, I need to solve some rust issue on passenger side. Looking from under the car everything looks good with the exception that the mid drive shaft bracket is completely loose due to floor rust. After removing all the carpet and any other floor covering the rust is superficial but covers the entire floor. There are some hole not more the 1 to 1 ½” diameter. With the holes not concentrated on a single spot I am concern that the rust eliminated a good part of the floor thickness. I do have a wire welder and all new metal. I even got a cupper plate today. The big question is to try to fill the existing holes or replace as much possible of the floor pan? I also do not run with a catalytic converter so there is no need for the bump on the floor.

Better to do a complete repair while you have it taken apart, then to wish you would have done it later. Rust is a PITA to weld through, it simply blows away.

redek wrote:Better to do a complete repair while you have it taken apart, then to wish you would have done it later. Rust is a PITA to weld through, it simply blows away.

I agree better to have a solid floor. The time to do it is now.

I think you are right, the rust has eaten away the structural integrity of the floor. I had tried to patch holes in metal like that before, and you find yourself not being able to weld the patch in: the metal next to it just disintegrates as you try to weld to it.

You could fabricate your own floor, or just buy the front floor section and cut off what you don't need.

I manage to start my newly installed engine and love the sound. I was really surprised how easy was to remove the old floor pan. I used a sharp chisel to break most of the spot welds, I grind down what was left. I also used an angle grinder and an electrical scissor to find my way around the rust. There is no more rust but there is no more floor pan also. Fred Flintstone style. To my surprise the after market front right pan is a perfect fit. It will be welded in place next weekend.

Looking good. If I recall correctly with my buddy's mustang... You just need to spot weld the new metal in place, and seal it with some seam sealer. Hope it turns out well, can't wait to see it.

What is the best way to do a spot welding? I have a spool wire welder and I was planning to drill small hole 1/8” to 3/16 on the new material on the overlapping area, then to weld over the holes. What material is recommended to seal the edges or overlapping welded area. I am making tiny steps to the completion. I did plan for 1-year restoration. Thank you guys

Yaba Daba Doo!!!

if you can put a pice of copper under the hole before you weld so you wont burn thru

I actually got a piece of copper for that reason but I was thinking if I drill a hole to the new material the melded wire material will fill the hole and adhere to the old metal and I will end up with almost factory finish. The front fenders where replace by the PO and the welds looks like s… with to much build out.

he was supose to grind them flat,then paint

lm48 wrote:What is the best way to do a spot welding? I have a spool wire welder and I was planning to drill small hole 1/8” to 3/16 on the new material on the overlapping area, then to weld over the holes. What material is recommended to seal the edges or overlapping welded area. I am making tiny steps to the completion. I did plan for 1-year restoration. Thank you guys

That's the way to do it, in welding class we called them plug welds. Make sure you have a specialized pair of vice grips to cinch the panels together, or use sheet metal screws (which will be removed later). When you are doing a butt weld, make a small spot weld every 1 to 2 inches. And then come back after the the panel cools to repeat the process. This method takes much longer but reduces the possibility of panel warp. I suggest you use por-15 (or other comparable product) to protect the metal from rusting away. And then use a seam sealer, just get an automotive seam sealer eastwoods, 3M, etc.

Hi Redek, I am a self-learner but mistakes are very expensive. I have no more the 3 h of welding experience but some thinks makes more sense to me then other, are like intuitive. I am already $2500 in this restoration, cost including 2 cars. And yes, I was looking to set in place the panels with screws and the fill the hole after the job is done. Thank you All

Giving up for today. I got the floor pan front and back in, fabricate a new brace for the seat. I will leave the seat supports for next weekend. Two days of hard work. Welding is not easy I still have to grind the welds, seal the edge and paint.

Looks good!