it's not just the weight of the gas in the tank, it's the slosh factor.
- you're lowering the tank  on a floor jack..............it's a little off
center, it tilts, the fuel sloshes to that side, and then it tilts a Whole
Bunch ! ....
and you wish you'd had it empty.
I even pump mine dry with the fuel pump before removing it.
And it really doesn't have to be that desperate a job.
I was just dealing with cross-over tube on top, and the plastic fittings for
that pipe, and the grommets , with the tank fully in place.........through
the wheel wells.  It wasn't that bad actually.   Takes some patience and
determination of course.............and WD-40 , but it wasn't all that bad.
Scott

----- Original Message -----
From: "pickle vanagon" <greenvanagon@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, September 08, 2008 8:41 AM
Subject: Re: Fuel Line replacement w/gas in tank

> Even if prices skyrocket to $4 by the time you finish the job (very
> unlikely!) you will have only saved yourself $7 or so.  Working on the gas
> tank is nerve racking enough as it is for me.  (And the gas tank is heavy
> enough as it is even when "nearly empty".).  I imagine that it is
> *possible*
> to to this job with the gas tank half-full or whatever, but it seems like
> a
> foolish idea to choose this route.  I bet you $7 that if you decide to do
> this, you will end up wishing the tank was empty.
>
> On Mon, Sep 8, 2008 at 8:03 AM, Michael Sullivan
> <sandwichhead@gmail.com>wrote:
>
>> Good morning, all. Will be replacing fuel lines this weekend and have
>> been
>> keeping my tank nearly empty in expectiation.  Would like to get some gas
>> today, though while prices are low(3.49US/gal). Will I have problems with
>> gas in the tank or is it better to be empty? Thanks.
>>
>> --
>> Michael in San Antonio
>> 91GL AT 'Gringo'
>>