Two questions on auxiliary gas tank

[CCCC]

While removing the bed, a paint/body guy poked a hole in the aux tank mounted just behind cab, in front of rear wheel. While the bed was off he brazed the hole, but it still weeps enough to be a problem.

1. This tank is wider at the top to fit the side panel contour and am wondering if there is enough clearance between the body and frame to drop it out - without removing the bed. Anyone know how these "not-square" aux tanks were installed? Maybe remove the rear wheel and it would slip out toward the back?

2. Is there a GOOD (meaning "really works well") product that would seal a small weep leak when applied to the outside of a gas tank?

Thanks for any info/advice.