The hose form the tank to the pump is 11mm. A 7/16" fuel filter should work.
You probably have a 3/8" with the clamps just tightened to compensate. With
today's moderns fuel distribution and quality there is no benefit to this
extra filter but if you really feel the need for a pre pump filter use the
original equipment style. The plastic filters designed for carbureted
applications are not designed for the flow our systems produce or the
suction our pumps can provide if the filter should start to plug up. The
pump won't work long once that paper gets sucked in. How much suction can
that pump supply? I have a number of tanks vacuum collapsed over the years.
Also it may not have the strength to withstand a road debris impact or some
other nasty creating just another failure point for the tank to empty
quickly.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Troy
Sent: Sunday, September 02, 2012 1:03 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Fram Gas filter

Hi Folks:

I have an 89 Westy, and trying to determine a suitable Fram (preferebly
clear) fuel filter to use. I understand the filter was not stock, but my van
has one, and see no harm leaving it in place. Problem is I have no ideal
what Fram filter has the 14mm barb ends, and is clear. Can somesome suggest
a filter to use? Does anyone know what year VW did away with the square
prefilter and went to 14mm from the tank to the fuel pump? Did the early
model have a charcoal canister filter or was that added later?

Troy