I've tried the internal
fuel tank sealer on my old Series 3 myself.
It didn't work & I ended up buying a new tank in the end. :roll:
When the tank on my Defender sprung a leak I decided to go straight for a new tank.
When the end seam on the fuel tank of the wagon at work sprung a leak, I cut the whole end of the tank off & welded a new piece of steel in. This did however make the tank a couple of gallons smaller. :lol:
The only reason I did it this way was that the cost of a replacement tank for the wagon was several hundred pounds.