On mine the crossover pipe had a crack and one grommet that the crossover went into was leaking.
That was about 100K ago and I am due for another replacement. (bother)

A number of list vendors sell all the needed parts as a kit.

Todd

'88 Westy

 -------------- Original message ----------------------
From: Mike S <mikes@FLATSURFACE.COM>
> At 06:52 PM 5/22/2007, Jack R. wrote...
> >What is a reasonable repair time to fix the ever present problem of
> >the
> >Vanagon Fuel tank leaking when filled up?
> >
> >I assume the below parts will cover the repair.
>
> It's also possible that the crossover pipe (or it's hard plastic
> fittings) has cracked or the small rubber vent hoses which connect to
> the overflow tanks have died.
>
> You may also want to do the rubber grommets for the overflow tanks at
> the same time.