I replaced the fuel pump in my '87 5000TQ over the weekend
(remember "Nosiy fuel pump" thread sometime back?). I bought the Bosch
pump from Halsey Imports for $145 (cheapest). Dealer price was $287 list
and $210 after discount (don't know if it was Carlsen Audi or Somerset Hills
Audi who quoted me this figure). Of the 8 or so places I called, no one
mentioned a revision to the pump or the holder. May be the revision applies
to later model years? Any way, the pump came with the check valve installed
but no holder. The holder in the car and the rubber mounting bushings were
in excellent condition, so I reused them.
The job took only 1 hr and 15 mins. Followed the sketchy procedure
in Bentley augmented by the procedures posted here by others. BUT, here's
the catch no one had alerted me to - the position of the fuel line connected
to the pump is critical - else it will interfere with the fuel gauge sender's
movement. I found out after I had put everything back together that the fuel
gauge was now showing the tank as half full when I knew it was only about
1/8 full. So I spent another 3 hours inside the trunk practically redoing
the job twice over to get it right. Although I was careful even the first
time, I didn't realize that if the hose is off even 1/4" to the wrong side,
the sender touches it.
I found that the fuel hose should be pointing in the 9 to 10 o'clock
position when you are in the trunk looking into the fuel tank (front of
car is 12 o'clock position, rear is 6). I suggest you mark the position of
the fuel line w.r.t the pump *and* holder before disassembling. Its not
easy to position the fuel line exactly where you want it since it rotates
as you are tightening the pressure fitting on. The filter can not be rotated
in the holder later for "fine-tuning" since there is a notch on the filter
that corresponds to a slot in the holder.
Anyway, I am satisfied with the job. Almost no noise with the
new pump and I can perceive improved performance from the engine (higher
fuel pressure I guess). BTW, the fuel tank was clean as a whistle inside -
no dirt or black stuff that others had mentioned seeing in their tanks.
Other pointers for doing the job:
Replace the copper (or aluminium) washers at the fuel line fittings. You need
four ordinary ones and one special one that goes on top of the check valve -
it has teeth-like serrations on its inside diameter. I bought them at the
dealer for about a dollar or so for all 5.
I found it easier to remove the thin fuel line from the bottom of the
sender (its connected to the fuel pump at the other end). Then remove the
fuel sender completely out of the tank leaving the other, thicker hose
connected. Then remove the fuel pump from the bottom of the tank
after unclipping it. Bentley seems to imply that the fuel pump can be
removed with the fuel sender partially removed. I think one runs the risk
of damaging the sender in this case.
Hope this helps.