I would guess that they are "brazed" in place.
EDIT -> Well there you go, Neal knows his stuff.
For safety, I'd say take to a local welder that knows how to work on gas tanks, as it's an explosive proposition (there are safe ways to do it, usually filling the tank with water and having no air spaces for gas fumes, even when dried out).

Or, you could try some epoxy material.
There is some vibration up to the tank, so you want it to hold together and not leak, but get some epoxy that is gasoline neutral, doesn't disolve in gas and won't produce debris into the gasoline.

Paved roads, just more needless government spending...

I pick up my mail in Santa Barbara, California, USA.

Last Edited By: allen pierce Mar 19 11 9:58 AM. Edited 1 times.