Although Audi makes many kinds of vehicles, the function of the fuel filter and the process for replacing it is similar throughout. The fuel filter separates out contaminants from the fuel before it reaches the carburettor, where it is mixed with air. Unlike in many vehicles, the fuel filter is located above the fuel tank. This positioning makes the process more difficult than in many vehicles, but it is still a straightforward process that shouldn't take more than 30 minutes.
Turn the Audi off if it was on. Set the emergency brake. Raise the vehicle from the rear-passenger side. Set the chassis on the jack stand for extra safety.
Slide the floor jack below the fuel tank. Loosen the four bolts that secure the fuel tank in place with your socket wrench set. Raise the floor jack to about 5 inches below the fuel tank. Remove the four bolts and lower the fuel tank onto the floor jack.
Remove the bolt securing the fuel filter strap to the fuel filter and fuel tank. Loosen the strap.
Place a dripping pan below the fuel filter and surround it with disposable towels. Remove the banjo bolts securing the fuel tubes to the fuel filter with your socket wrench or crescent wrench. Allow the fuel to drip into the pan. Pull the fuel filter out of its strap.
Insert the replacement fuel filter into the strap and secure it in place with the bolt you removed earlier. Attach the two fuel tubes. Raise the fuel tank into its original position and secure it with the four bolts. Lower the vehicle.