Removing and installing fuel delivery unit - vehicles with 6-cylinder and 8-cylinder engine — AUDI

🧭 Before you start

Drain the tank, disconnect the banjo bolt, fuel pipes and connectors, and undo the union nut. Loosen and press the centre bolt to free the unit from the adapter plate, lift it about 40 mm and turn it out in 45° steps. Check the filler pipe and baffle housing, fit a new O-ring and sealing element, trial-fit without the flange seal, then install with the new seal, tighten the bolt and union nut and leak-check.

Fits: Audi A8 D2 (4D)

• Renewed: seals for banjo bolts

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• Secure the fuel gauge sender connector before fitting; it cannot be reached once the unit is in.
• Trial-fit the unit without the flange seal to confirm the supply pipe sits in the adapter plate funnel.
• The flange must lie flat and the bolt slide in smoothly, or the job will need repeating.
• Renew the O-rings, sealing element, flange seal and banjo bolt seals.
• Leak-check the fuel delivery unit afterwards; it is the only way to confirm the baffle housing seals.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

📐 60 workshop diagrams for AFB

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Observe safety precautions .
2. Observe rules for cleanliness . [Note: Before starting work, mechanics should have seen Video Film No. 23 "“Audi TV Special, 25.06.1997: A8 Tank Repair”".Prior to removing and installing the fuel delivery unit, it is advisable to take the tool kit and spare wheel out of the luggage compartment. You can then sit or kneel in the spare wheel well. This makes it much easier to install the fuel delivery unit.]
3. Drain fuel tank completely. Procedure with intact fuel delivery unit ; procedure with defective fuel delivery unit .
4. Remove banjo bolt (3) for fuel supply pipe to additional/auxiliary heater.
5. Disconnect fuel supply pipe (5) and fuel return pipe (4).

6. Unplug electrical connectors (1) and (2).
7. Unscrew union nut using union nut tool T40068 A.
8. Loosen bolt (1) several turns, but do not remove.
9. Press firmly on bolt (arrow) to separate fuel delivery unit from adapter plate in fuel tank,
10. Unscrew bolt completely and take out.
11. Pull fuel delivery unit upwards by approx. 40 mm while moving it slightly backwards and forwards.
12. Pull seal off rim of assembly opening.
13. Turn fuel delivery unit approx. 45° in clockwise direction (flange moves upwards).
14. Turn fuel delivery unit approx. 45° further in clockwise direction while pulling upwards.
15. Now turn fuel delivery unit approx. 45° in anti-clockwise direction while pulling upwards.
16. Pull fuel delivery unit out of fuel tank in position shown in illustration. [Note: When removing from luggage compartment, hold cloth under fuel delivery unit to catch escaping fuel.]
17. Empty fuel delivery unit into a suitable container. [Note: Observe disposal regulations for fuel.]
18. Prior to installation, check that filler pipe (1) is clipped to adapter plate (2) with pipe holder (arrow). [Note: The illustration shows a sectional view of the fuel tank from the front.Proper attachment of the filler pipe can be checked with a mirror and an electric hand torch (flashlight).If the adapter plate is not clipped to the filler pipe, the fuel delivery unit cannot be properly installed or the adapter plate will be damaged when it is fitted.]
19. Before inserting fuel delivery unit, inspect baffle housing, bottom section of baffle housing and connectors for suction jet pump pipes (visual check).
20. Renew O-ring (1) and sealing element (3) and check installation position.
21. Secure electrical wiring with connector (2) for fuel gauge senderG as shown in illustration. [Note: The electrical connector is not accessible after the fuel delivery unit has been installed.]
22. Start by installing fuel delivery unit without seal for flange.
23. Hold fuel delivery unit in position shown in illustration.
24. Insert fuel delivery unit in fuel tank, at the same time turning approx. 90° in clockwise direction.
25. Tilt flange of fuel delivery unit (1) into position shown in illustration so that bottom section of fuel delivery unit is swivelled to left as far as possible.
26. Now turn fuel delivery unit 45° in anti-clockwise direction; fuel delivery unit is thus inserted into fuel tank.
27. Turn fuel delivery unit another 45° in anti-clockwise direction; fuel delivery unit is now in installation position.
28. Hold flange in installation position at a distance of approx. 40 mm above assembly opening.
29. Check installation position:
30. Now press fuel delivery unit down. [Note: If the supply pipe is not inserted in the funnel on the adapter plate, the suction jet pumps will not function and the fuel delivery unit will not be sealed off from the adapter plate.If the baffle housing leaks or the suction jet pumps do not function, the engine will stop due to fuel starvation although the fuel tank is still 1/3 ...1/4 full.]
31. ⚠ Risk of repeat repair.The following requirements must be met to ensure proper installation:The flange of the fuel delivery unit must rest flat and straight on the opening in the fuel tank.The bolt must slide easily and smoothly into the tapped hole in the adapter plate and it must screw easily and smoothly into the thread.If these requirements are not met, repeat the installation procedure. — After checking installation position, pull out fuel delivery unit approx. 40 mm again.
32. Fit new seal in rim of opening in fuel tank.
33. Install fuel delivery unit again.
34. Fit new O-ring (1) onto bolt (2).
35. On vehicles with additional/auxiliary heater, make sure restrictor pipe (3) is inserted in hollow bolt.
36. Screw in bolt (arrow) initially hand-tight.
37. Fit union nut and tighten using union nut tool T40068 A.
38. Tighten bolt (arrow).
39. Renew seals for banjo bolts.
40. Tighten banjo bolt (3) for fuel supply pipe to additional/auxiliary heater.
41. Attach fuel return pipe (4) and fuel supply pipe (5) and secure with new hose clip.
42. Plug in electrical connectors (1) and (2).
43. Install fuel gauge senderG (right-side) .
44. Check fuel delivery unit for leaks . [Note: The fuel delivery unit must be checked for leaks after re-installing . This is the only way of ensuring that the baffle housing is not leaking.If the baffle housing leaks, the engine will stop due to fuel starvation although the tank is still 1/3 ...1/4 full.]

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