Gas Tank Pressurized problems!?!?

[Zachavez2008]

Have a 1976 GMC K1500 and I have been having some gas tank problems!!! Got home one day and found gas coming out of the cap which cause my paint to bubble. So I dropped the tank and changed all the hose's to the fuel switch valve. Note this is the passenger side tank which I never use !!! Put all new hose in get home yesterday now its dumping fuel out of the vent valve. Only does it when it gets hot I do live in Az. Seems like tank is getting pressurized what could be my problem need some help here guys

 

[Charlie]

 

[bedwards]

My guess is your tank selector valve is either bad or leaky. I had that prob on my '85. It was pumping gas from one tank to the other and then, when the tank was full, it went into the vent lines to the canister and then to the air cleaner where it flooded the truck out.