The fuel pump is inside the fuel tank. The bottom of the pump is secured to the bottom of the tank by a bayonet style mount. Access to the top of the tank is provided by a panel on the floor of the cabin in between the seats.
Remove the driver's seat.
Remove the cover on the hand brake. Lift up at the base of the cover. It's held on to hand brake assembly by plastic clips. Disconnect the wiring from the hand brake. Remove the three nuts holding down the hand brake assembly. The two nuts closest to the driver's door can be removed fairly easily with an end wrench. The nut closest to the middle of the vehicle is difficult to access. If necessary, cut a cross into the carpet, put a socket on the nut, and push the carpet down over it so it can be engaged with a ratchet.
You can see part of the fuel pump access panel under the hand brake. Start a cut in the carpet to expose more of the access panel.
You're cutting blind here. The cut shown here was not too bad, but could have been a little better if it had been further 'north' so it met the third access panel screw.
Remove the access panel, fold back the carpet and secure it with clamps.
Remove the hoses and wiring from the flange. A special purpose tool can help with removing and installing the ring. NC- In the plug, the Brown wires are grounds, the Red and Yellow Stripe wire is 12V for the pump, and the purple wire is for the fuel level sending unit. The thicker Brown wire should be the pump running ground, and the thinner Brown is the sending unit.
Lift off the flange.
The pump is secured to the bottom of the tank with a bayonet mount. Without damaging the fuel level sending unit, carefully turn the fuel pump to release it from the bayonet mount. Remove the fuel pump from the tank with the fuel level sending unit still attached to the side.
The clamps on the internal hoses are special Oetiker 'stepless' clamps. These are 11.9 mm clamps. The VW part number is N-103-100-01. A special tool is required to install these clamps.
The pump shown here has an obvious defect. The plastic case of the pump has expanded around the top and popped out from under the metal rim around the top edge. Symptoms of this pump's failure involved cutting power when trying to accelerate down from a mountain pass.
The bottom of the carrier holding the pump is secured to the bottom of the fuel tank by a bayonet mechanism that you can see on the inner area of this ring.
There are four tabs on this mechanism. Two of them are flat. That is, they don't have a catching mechanism.
The other two tabs will catch and hold when the pump is installed.
Note that the tabs with catches have holes. It isn't known whether these accomodate a releasing mechanism. [The specially shaped holes are there to adjust flexibility of the locking point on the tab such that it will come apart without breaking. so vw expected maint here, actually considered dissassembly :-D this note added by KTPierce]
The photos above are of a stock 1997 EVC fuel pump carrier. Replacement parts may not be identical in all respects.