Ask and you shall recieve! (Flip Top Gas cap Adapter)

I haven't had this happen yet. Do you fill it that full or drive that crazy? Lol
No but really. There is a putty made spefically for fuel leaks in tanks. Maybe that will work? Maybe a better solution is making a gasket from material you can buy at the parts store. I' kind of surprised that you are having the issue though. I have contimplated getting gaskets made too, but id have to adjust the price to cover the costs of course. But as I said. I have yet to have any issues.