If the pre pump filter has the same size hose on both sides then it was the
original that should have been removed during the first service. If it uses
a smaller hose for the inlet then the one to the pump then your tank has
been replaced with one of the low cost replacements and the filter is also
being used as an adapter.   The larger filter after the pump is designed to
filter on the pressure side. This allows for finer filtration and eliminates
the filter as a cause of vapor lock and pump cavitation. It also increases
service intervals. If the tank is loaded with crud the real fix is going to
be replacing it as the crud is from the tank itself failing. At some point
cleaning it will only delay the replacement as the next step will be
leakage.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Troy
Sent: Monday, February 20, 2012 4:05 PM
To: vanagon@GERRY.VANAGON.COM
Subject: gasoline prefilter

Hi folks:

I have an 89 vanagon westy. I have a square prefilter before the main
canister fuel pump, and I'm told this is not a stock set up. I have also
read in various posts how rust/sediment in the tank can get lodged in the
fuel pump, so wondering if I should just leave the square prefilter in place
when I replace my fuel pump. Is there any harm to doing this? It apparently
has been working fine for years this way.

Troy