Look on the top of your tank where all the vent lines and hoses go into
the tank, there are some seals there that might need replacing, the hose
is supposed to shut off on its own.  Do not take this to the shop or you
will pay about 200.00 bucks to get it fixed, thats what mine cost me
after I dropped the tank without knowing about the seals on top, you
should be able to replace them yourself.

        DrRufo
        SOCal-81 vanagon