[Billy]

Hello all, I am wondering which is the right way to go or if it matters.

I have a 67 Cougar with big 'ol rust holes where the seat plugs go, a giant hole in the front floor to firewall area (I can see into torque box, box looks ok), and a few smaller holes elsewhere.

I ordered a 6 piece replacement set that includes the area from the back of front seat to firewall, behind front seat to rear seat, and floor to firewall pans.

I am starting to cut out the old and I have a few questions:

-Should I try to cut the old/new to match perfectly and butt weld the entire piece, or is some overlap OK? I was thinking of overlapping on the driveshaft hump and part of the firewall and butting the front and rear edges to the existing floor. If I overlap, do I need to weld top and bottom completely? Or "spot weld" it and seam seal it? I am worried about rust in the future. I think it will be nearly impossible to cut the hole and replacement panel to match perfectly. The outboard edge has a flange that I can weld to door sill (spot or completely??)

-For small areas (like a penny or finger size rust hole: should I cut out the section and weld in new? Or patch / fill with weld?

-I removed enough floor to expose the frame rail (unibody). Should I weld the entire edge from underneath to the new floor piece? Or mark from bottom, drill small holes, then "spot" weld from the top?

-I removed the parking brake cable bracket that was attached to the floor on passenger side. Can I get a new one of these? How do I go about lining it up? (unfortunately, i did not take measurements before I cut up that section)

-I searched the web for some good YouTube videos and images of floor replacement and I didn't find any "good" ones. Most were abreviated or music-video-like.

-What should I paint the new / old floor with? I was thinking brush or roller to minimize overspray but I am open to ideas.

I think we'll need to keep this thread around for awhile. I am gonna need lots of advice on this part of the resto.

Thanks!

 

[Al Bundy]

If you pick up a copy of last months (I think) Muscle Machines, there is a good article on replacing floor pans.

 

[Billy]

Thanks. This one?

 

[1969XR7Vert]

FWIW Billy, If you can see into the torque box, then the upper panel of the box is gone! The TB is a three-sided structure and the face in question lays up against the part of the floor you have indicated is rotted out. Look up a replacement TB picture and see what I am talking about.

Bob

 

[Billy]

Thank you. I was wondering what it was supposed to look like. I could tell there was at least two layers of metal but I couldn't make out the original configuration. Do I need to replace the entire torque box then? If yes, prepare for a few more questions

 

[1969XR7Vert]

Well Billy,

I think the answer is yes, but some people have separated the two pieces and put them in separately and then welded them back together in place. I'd imagine you could extend the concept to putting a piece of new and joining to the old if the old is in good shape. You might call Tom at KTL (www.ktlrestorations.com) and ask him. Tom is a master of this sort of thing. I replaced the TB's in total, mostly because it was easier to replace the inner rockers (convertible) that way.

 

[Al Bundy]

Thanks. This one?
View attachment 29716

That's the one.

 

[67.5xr7]

Lap the tunnel at approx. 1 1/4" overlap, butt weld under rear seat and butt weld the firewall/foot panel. Spot weld inner rocker flange, tunnel and where the front pan overlaps the rear pan. In the spot weld areas, align and attach with self tapping screws approx. one every inch,...use the screws in a zig-zag pattern on the tunnel. Turn your mig to a higher temp that normal,....pull a screw and weld up the screw hole. If you want really good penetrating spot welds,.... once you pull a screw out, use a drill bit about twice the size of the original screw hole and bevel the top layer of sheet metal with the drill tip.

PS. On the frame rail extensions and torque boxes,..spot weld. Set a couple screws from the underside to establish the perimeter, then set the remaining screws from the topside.

 

[highrolla7]

Just did mine and I cut out old floor. Then I overlapped the new floor and welded. I would say about 1 inch to 1 1/2 lap and welded from inside. I also did the torque box which was a 2 piece and was easy to install. Also did part of the firewall with scrap metal. Turned out nice. I plan on sealing the bottom with a sealer that looks like caulk. I just went around the edges off the floor extensions with a few spot welds and that worked well. Not worried about rust or anything I don't drive in the rain or snow.

 

[Billy]

Awesome, I have some great direction now. I've got most of the old floor out and have started fitting the new. I appreciate the tips, a lot. Thanks.
Btw

If you pick up a copy of last months (I think) Muscle Machines, there is a good article on replacing floor pans.

I received the magazine and it is pretty darn similar to what you guys said above and has some nice photos. I never thought of using the screws first. Thanks again. I will try to get some picks up soon.