Did you just fill the tank? If so you just put too much in or filled it while bus was slightly tilted to drivers side. The vent portion of the cap relieves pressure from vapor build up. Take fuel inlet hose on fuel pump off and drain about 3/4 gallon into a can. It's a slow way to drain fuel from the tank but easiest and safest provided you don't smoke. Just lower hose below tank level and it gravity feeds out. Remember the 67 has the hump so it's possible to overfill if not completely level. That is if you have a full tank of gas. Hope this helps. Best Ken Sent by pure magic On Nov 4, 2013, at 9:26 AM, Sharon Chamberlain <sharonvws@xxxxxxxxx> wrote: > I need some advice on our 67 westy- gas pressure builds up and it runs out > from near the gas cap-we were planning on leaving tomorrow morn for Florida > shows . Anyone got an idea why and how to fix it. Steve thinks all we need to > do is buy a vented cap, we have an original one on there now. Don't want to > be a fireball. HELP