Fuel tank on old '82 100

[quk@sievers.com (Phil Payne)]

In message <6148001223051997/A17459/IC1/11B5BB002D00*@MHS.ithaca.edu> FMARTIN writes:

> I can't help you with the tank-replacement information, but in the *meantime*, 
> to lessen the continual re-fouling of your fuel system, you might want to 
> consider doing what I did for an old car of mine (not an Audi). This car had a 
> similar problem/challenge; different cause. After looking at what replacing 
> the gas tank might cost in time and energy, I went to the local *big* auto 
> parts store and looked over their rack of aftermarket-fuel filters. I found 
> one that is translucent, sizeable, and in what I call a "drop 
> configuration"...inlet and outlets at same level, with the filter hanging 
> below, so as to catch crap and water. I installed this as close to the tank as 
> possible, and check/dump it every couple months. Did the trick for me, at a 
> cost of about $8, 25K miles ago. 

Audi part # 811 201 511D.
 
> Don't know if this would work for you (mounting space? fuel line materials? 
> too-high system pressure?), but worth looking into, for at least a cheap, 
> temporary fix??

Yeah.  The drawings in the parts fiche show this thing on my car, but it wasn't 
physically present.  The mounting lug was bent up against the underside of the 
car, and this had obviously been done before the underseal was applied.  While 
the existence or otherwise of an Audi TSB deleting the thing was debated, I 
went ahead and refitted it.
 
It's not hard.  I used a brake line clamping device that I bought _years_ ago 
and have never used for its intended purpose to clamp the fuel line from the 
tank.  Then I mounted the above-named Audi part (plus a bonded rubber bush, 
etc.), chopped a lump out of the fuel line and connected the ends.
 
I have debated in private email with a number of people whether this was a good 
idea.  Audi deliberately deleted the part (it's actually _not_ a filter, but a 
sediment trap ideal for catching tank debris), and the question is - why?
 
I suspect the heavy hand of the German TUEV.  "Eingriff", as they say, into the 
fuel lines is frowned on.  I suspect Audi deleted the part because the TUEV 
didn't like the idea of garage mechanics dumping entire tanks of fuel upon 
themselves.  You would be _amazed_ at how quickly 23 gallons can pass through a 
13mm hose.
 
Anyway, I fitted it.  I've had no problems that can be traced to its existence, 
and a powerful workshop light shows that it has trapped a piece of SH1T about 
3mm by 1mm.

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club