Fuel tank breather not breathing

[Giantsniners72]

Im having a problem where if it gets a little warm out with a full tank, i get fuel leaks from either the rear behind the driver side tire or in the front in front of the passenger side tire. It only adds up to where the breather lines are not doing their job. I replaced all the breather lines, Bout 2 different gas caps, and still leaks. Im stumped. does anyone know where i should look? Thanks for any info!