Leaks can be stressfull because they can start there and water will end up here. Wife insisted it was the belly band (I was too timid to undertake the task) so I disagreed and just filled holes of missing rivets with epoxy.
That didn't cure the problem.
17 years of finding water in the Boler
and this past summer was the 1st year it stayed dry inside...YIPEEE.
Tell us where the puddle is and we may be able to tell more?
When you say big HMMM I can imagine like an inch of water on the whole floor or is it just a corner that has like a pool?
So sorry, I have no advice on the belly band but on my 79Boler I found the leak after years of finding the rear road side bench seat wet after a rain. Wife would say the seat is wet and before I went to look she had cleaned all the water so traceing it was hard but then I found, when I stood out there in a rain storm, a little river of water, traveling along the back of the kitchen counter and it was actually comeing in the Jealouse window that's over the stove.
Over the years I have done all but taken the Jealouse window out myself, even had a window dealer, supposedly remove and re-seal ALL windows
then had a trailer dealership re-seal rear window because the window dealer didn't fix it the first time, I spent about an hour inspecting that crank out window and had an AH-Ha sighting.
In the corner of the tiin frame, where it fold over to make the corners, there was a seam, where the solder was missing.
I had some self sticking aluminum sided tape and cut like a 1/2 strip and fashioned it to go along bottom and up the sides of this frame.
I knew water can get in by the window but now it can not get into this seam and can just flow out under the window where there is not a 100% seal.
Point is a leak in the front ends up on bed in the rear.