Hi,
I have a '76 F-150 with a 360 V8, RWD and a rear-mount 19.2-gallon tank. I have trouble when I fill up because it backs up if I pump full speed, and when I go around corners the gas sloshes out. I bought a new locking non-evaporative emissions (no charcoal canister for me) gas cap because I thought that would solve it. No. Today the gas was just trickling out while parked (almost full tank) and when I unlocked it and tilted it to slowly release pressure gas squirted out all over me and gushed onto the ground. It was like it barfed on me but it wasn't even hot out! Is it the tank, hose, vent tube or what?
I appreciate the help!

 

Plugged vent is what does this. My '76 has the same issue

 

Fuel guys, including Fastredtruck and squirrel Man Sam, I have been working on restoring a 77 Ford F 150 Highboy with 400 w/O emmisions. This AM I loosened the rear tank fuel cap and the small hole on the black plastic square piece that is between the fuel tank door and around the filler neck is making a small constant stream of fuel and I found there has pressure in the tank. There's no return line on this model no evap emmisions and has what appears to be factory caps on the rear tank fuel door and to the behind the seat tank. Can anybody shed any light on where this plugged vent can be found. By the way, Thanks FTE members for being a great place to share info