[urq] Fuel system rot

[Chris Miller]

On my tank, the two connections at the bottom had corrosion.  I think
condensation in the trunk area drains/collects here.  You might be able to
use POR 15 to rehab the two lines if just perforated but mostly intact.

For the filler neck, it is just a tube.  Is the rust at the opening where
you refuel, or the whole thing?  I would think you could cut off the end of
a 4kq or similar filler neck and use a rubber hose and two hose clamps to
connect with the original filler neck.

I fit a 4kq tank to the urq, but haven't added fuel etc. yet as the project
is on hold while I find $$$ and time.  Filler neck angle is wrong, did some
bending, hope it works.  May have to cut off the 4kq neck and use the urq
neck.

On the 4000 forum on quattroworld, there are photos of the inside of the
tank.  At the base there is a separate compartment (the depression on the
base of the tank), with a long slot allowing in fuel.  That is where the
pickup tube and filter sock resides.  You can't just line the tank without
first taking out the filter sock in some manner.  Might be able to grab it
with something through the hole for the fuel level sender.

If you think the tank is rusty and have to replace the two lines at the
bottom, consider a fuel cell.  If not, then consider cutting the bottom off
the tank, replacing the two lines, and resoldering up the opening.  You have
to get all of the fuel and vapors out prior to any cutting; the local fire
department may have a sniffer that can certify there are no vapors remaining
in the tank.

I may go that route with the original urq tank.  25 years of old fuel left a
crusty solid in the base that won't dissolve... bounces around like bits of
rotted wood.

Chris

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf
Of Jon Archibald
Sent: Saturday, May 25, 2013 1:45 PM
To: urq at audifans.com
Subject: [urq] Fuel system rot

Gruppe,
Well it appears I have screwed up (another) good thing through negligence.
At 79k, the '85 3B'er is leaking from the bottom of the tank, at least the
pressure lines d/s of the pump, and possibly at the corroded filler neck.

Unfortunately I brought this upon myself, I believe, by repeatedly storing
the car for months and months over the past 13 years with either very little
gas and/or no stabilizer. The problem is that the car -has- usually been
driveable so I never -plan- to store it long term with just a few gallons in
it, but weeks turn into months quickly, I get busy, and suddenly it's been 6
months. Has happened many times.

So...at a minimum I think I am looking at tank repair/replacement, repairing
a hard line with a leak, possibly rehabbing the crusty filler neck, and
trying to reinvent correct tank ventilation which has not been right since
the West Orlando Swappers who originally put the engine in decided to just
break off every pipe coming out of the firewall they did not want to deal
with.

Ughh...

So I know none of these is a new problem, but since the cause is ostensibly
just idiocy on my part for not storing the car properly, interested in
big-picture concerns I should have (other shoes waiting to drop), experience
with crusty filler necks, any the latest on repair/replace opinions on
28-year old fuel tanks that have rusted through.

Thanks and have a great holiday weekend!
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