fuel filler neck overflow

[kenward1000]

71 240z new to me.  Thursday night I filled with gas, adding enough extra after the pump shut off, that I could see gas down in the neck, maybe 4".  Intended to drive it the next day but did other things.  Friday afternoon got to 85F, I walked by it and saw a little pool of gas on the pavement and gas seeping from under the filler cap.  Cursed myself, got a turkey baster and sucked gas out until it was barely visible again, which is about 4" down.  Saturday afternoon got to 90F again, and gas was seeping out a second time.  Sucked it out again.  Today it's done it for the third time in 95F temps!  

Unfamiliar with how the expansion tank and vent system is supposed to work.  Would like to buy a clue, please.

[dutchzcarguy]

After 40+ years the rubber hose on the filler tank inlet gets hard and does no longer make a solid fuelproof connection to the tank, especially when you've take it apart once..  (ask me how i know ?)  Just put enough gas in it, not completely full unless your going to drive a 20+ miles after filling right away.

In europe we don't have the expansion tank so i removed that leaky stuff..  I've seen those tanks with cracks..  logical after 40+ years in contact with gas..  Remove or renew.