Floorboard to firewall connection

[Bongo68]

Installing a tremec 500 in my 68 c10 and noticed alot of movement between the floorboard and firewall seam when I was measuring to cut floorboard. Question is was that seam just sealed or spot welded? If it was just sealed has anyone ever spot welded it? My game plane was to do both. Doing tranny mockup now but later on down the road will have to replace rocker pnls and typical floorboard rust along with this issue.

[RustyPile]

Looks to me like you have a water leak somewhere above and the moisture collected in the seam.. Rust has formed and caused the spot welds to turn loose.. The floor is gone, and possibly the lower part of the firewall. You'll need replacement panels.. Be sure to find the source of the leak and fix that too.. My guess is the leak is in the windshield area..

[Bongo68]

The windshield has never leaked that I know of but will take closer look. (My father bought this truck new when I was 2 months old and gave it to me when I started to drive). The way it looks to me is that the seam sealant deteriorated and water was getting in at the joint. So your saying that joint was spot welded? Cause I look carefully and couldn't see any evidence of spot welds. That whole seam is loose from drivers to passenger side.

[57taskforce]

Originally Posted by Bongo68

The windshield has never leaked that I know of but will take closer look. (My father bought this truck new when I was 2 months old and gave it to me when I started to drive). The way it looks to me is that the seam sealant deteriorated and water was getting in at the joint. So your saying that joint was spot welded? Cause I look carefully and couldn't see any evidence of spot welds. That whole seam is loose from drivers to passenger side.

Yes it is spot welded on the outside of the cab let me see if I have any pictures.

[Peanut74]

Yes, it is spot welded and seam sealant applied at the factory. I just finished repairing that section of my floor on the drivers side. As stated previously the spot welds are on the seam in the engine bay. If you sand off the paint on that seam the spot welds can be seen.

[Bongo68]

Cool thanks. I'll take a closer look. From what my dad was saying, back in the day when you brought a car you could have the dealership spray a under coat for more protection and that stuff is pretty thick, thats what I have. Thanks again!

[67swb72klb]

I have seen spot welds that have failed in that area that I have repaired on a cab or two..

[RodnRudy]

The rust around the pedal pins is probably from the area getting wet over time from the drivers shoes/boots. The spot welds on the toe board/floor pan seam on my 68 barely held it together. When I cleaned out the old seam sealer I clamped the seam back together and put stringer welds along the seam.