I always worry about gas tank sealers coming apart in the future. What I would do is remove the tank, clean area really well with acetone, get some new and improved gas tank seal (impervious to ethanol), lay the tank on it's front (engine area down), use a small wedge to slightly pry open the gap if any, use painters tape as a lower barrier and slowly dribble in the sealer until it comes out evenly on the bottom. Then put something soft on the tank top, use a piece of wood and clamp the drop down for a few days. The sealer becomes a seal and a bond.....then use the '31 column bracket.
Or you can try to get it warm enough to let the solder/lead flow a little. But be careful to not get it too warm and have it flow out.