I turn to the collective wisdom of the world...
     
     I just got my nice repro gas cap with VW emblem (tm), and it fits all 
     snug on my gas tank, but when I cam to fill up and remove the cap the 
     tank was under pressure.
     
     So..
     
     Is the gas cap supposed to seal like that or is there a tank vent that 
     might be blocked ? I took the cap off just to be sure.
     
     Lee
     
     '64 samba