This article provides series of instructions by following it, changing the fuel filter on a 1997 Audi A4 will be a piece of cake!
DIY Guide to Change the Fuel Filter on a 1997 Audi A4
There are four 13mm bolts, which hold the tank straps to the body. Remove them without removing the straps.
Next, detach cable from the front side of the tank. There are two plastic clips on the tank.
Now, using a pry bar with ease pry the front of the gas tank down enough to slip a 2×4 up and kind of on top of the tank, this will hold the tank in the downward position.
By using a 8mm 12pt 3/8 drive Allen and a 8mm ratcheting gear wrench to remove the bolt that keeps the filter strap to the side of the tank.
Detaching the Lower Banjo Bolt
Now, you need to detach the lower banjo bolt attaching the fuel line to the filter 19mm socket. Just be aware that fuel system may be under pressure, which could lead to leakage of pint of fuel from the system. Keep your rag handy.
You will now be able to grab and pull the filter out and be able to detach the 17mm banjo attaching the other line to the filter. There is no way possible way to reverse the lines or the filter; they have one large and one small hole where the lines attach.
Tip: Do not forget to replace the sealing washers when you replace the filter.