I busted the tank in the liquid-cooled machine (don't store sharp stuff in the driver's compartment when you travel) and fixed it the same way I do the bodies. I use a soldering gun and make welding "rods" out of an old poly body. Do a small section at a time and use the back side of a large kitchen spoon to cool and shape the plastic. I did the tank at least a year ago and it's still holding.
Good luck with it.
Stuck in the seventies- not in the swamp.
(12) Attex, (2) Hustler, (1) RIM, (1) Super Swamp Fox, (1) Tricart, (1) Tricub, the Gerber "B/A" Springer and a Starcraft! ...so far