I just did my 'maintainence' under the van, too.  I added an inline metal
filter, from a Triumph MC actually, between the tank and the pump inlet
because I had it and because the fuel pumps are costly to replace and the
filter isn't...I think maybe $15 or so...probably much cheaper if it didn't
say "Triumph" on it...  I didn't cut open my bosch filter but I did put
about 120 psi of air into the outlet and blow it onto a white paper
towel....no chunks no grit came out.
  I checked all my one year old fuel line and it looked perfect still.  I
didn't replace my (jetta 1.8l inline) fuel rail with the metal one I have
waiting, yet.
  I dunno why VW put the filter down stream of the fuel pump in the first
place...but I bet someone will tell us.

  Don Hanson

On Thu, Jun 3, 2010 at 7:08 PM, Max Wellhouse <dimwittedmoose@cfu.net>wrote:

> I've been using a 1/2" gas valve shutoff upstream of my upstream fuel
> filter for several years now to make th upstream and downstream
> filter changing a little less of a hassle.  It also makes a decent
> cheapy theft deterrent if you park in nasty neighborhoods.
>
> Last night I pulled the upstream filter and the downstream filter for
> annual replacement and decided to see what they had caught in a year's
> time.
>
> The downstream filter was made in Poland and I think I bought it at
> an AutoZone or Advanced Auto, so I doubt that it was a Bosch.  It had
> an aluminum housing as opposed to steel.  It had it's share of dark
> colored stuff, but no chunks of rusty gas tank or anything like that
> further supporting my theory that an upstream filter  is the best
> protection you can give your fuel pump other than keeping from
> running the tank dry trying to make the next gas station.
>
> Since my 90 GL: didn't have an upstream filter in it to begin with, I
> put a metal in line filter from WIX in there that had male 1/2" barbs
> on each end.  Current part number is 33248. There's a 5 in front of
> those 5 numbers, but the local parts guy told me that the first
> number simply denotes where the filter was made. They make a plastic
> one too in the same configuration, but I don't have that number
> handy. Paid like $11 for the metal one and the replacement Bosch
> filter for the downstream side is likely the spare I got from Bus
> Depot some time ago.
>
> Cut the Wix apart first as my 2 wheeled pipe cutter jaws were just
> slightly too small to open it up that way.  I unfolded the filter
> media and to my surprise there were no rusty chunks of gas tank in
> there.  What was curious though, was all the dried grit stuck to the
> circumference of the inner metal walls.  Sure glad all that didn't go
> through my fuel pump.
>
> Those contemplating doing this mod, there is plenty of horizontal
> room for the valve and the Wix filter between the tank and the pump,
> but I might need to research just how important it is to have
> unrestricted flow from the tank to the pump as the valve body opening
> diameter might not be equal to the diamter of the hose, and as the
> upstream filter clogs up, that could I guess cause stress to the
> pump.  The van's been getting like 5k a year drive time, so longer
> driving might need more frequent filter changing.
>
> YMMV
>
> DM&FS
>