69' Super Bee rear quarter internal gap issue

[440beep]

My '69 Super Bee has new rear side quarters on it, and since I've had the car, the trunk continues to accumulate sand and dust. I thought I found and sealed all the gaps, but I discovered a massive one this past weekend. I rested a shop light against the left side fender inside the trunk, shut the garage light off, and searched for light coming through under the car. I saw a massive stream of light running the entire length of the quarter panel where I think the truck floor should be sealed to the quarter. It looks I have to fix it from inside the trunk and not sure I can get the seam sealer caulk gun down where the gap is.

Here's a crazy thought, can I use a can of the expanding insulation foam and spray it down where the gap is and hopefully when it expands it will close the gap? Or what is the correct way to seal up the trunk floor to the rear side quarters on a car that is already driving? Is there supposed to be a gap between the trunk floor and the quarter panet on the inside that you stick your hand down in? Or is this where the trunk extension goes?

I'm just tired of having the sandbox in the trunk.

 

[wannadrag]

Don't use spray foam,that stuff holds moisture.Post a photo of the area looking from the bottom of the car. The trunk floor extension is sorta L shaped and gets spot welded to the trunk floor and also at the bottom of the 1/4.

 

[440beep]

Here's some pictures. The first picture is laying on the ground, looking at the inside of the quarter panel, and white arrow points to where I can see the light coming through from the trunk. Guessing somehow I need to seal up that big gap between the two panels. And then a photo from inside the trunk which doesn't show much.

 

[1967coronet]

The gap you can stick your hand in ........ some models had a fiber board cover over that area, Im not positive on a 69 Bee. your unsealed seam looks like it could use a couple more tac welds, but if it feels solid with the two I can see, I would seam seal it from the bottom after cleaning it up. wipe it smooth with a rag wetted with some thinner before the sealer skins over.
undercoat once the sealer is dry.
On the bottom were the outer qt skin meets the inner panel behind the wheel there will be a front and back drain hole.
Make sure they are open.

 

[Fran Blacker]

Piece of hose on chalk gun nozzle, the clear hose.

 

[WileE]

There is a gap inside the trunk in between the quarter panel and the floor extension. They mate at the bottom lip, it looks like someone did a crappy tack weld on yours. But, you can apply seam sealer from underneath. Use the caulk type to squirt into the seam, then finish with thick brushable seam sealer. Go to an auto body supplier.( and yes, as noted earlier, don't cover the drain opening)