Fig. 4-12 is an exploded view of the fuel pump assembly. On cars equipped with CIS, CIS-E, or CIS-E Motronic the check valve is available for replacement as a separate part. The Digifant pump is similar, but the check valve is not replaceable.
Exploded view of fuel pump assembly.
Always use a new O-ring when installing a new fuel pump or reinstalling the old one. On CIS, CIS-E, and CIS-E Motronic fuel pumps, always use new sealing washers on the fuel line connections.
Replacement pumps may be equipped with a new style positive-lock connector. If so, the mating connector in the wiring harness will have to be changed. Check with an authorized Volkswagen dealer parts department.
Disconnect the negative (-) battery cable from the battery.
Working beneath the car, disconnect the harness connector from the fuel pump. Thoroughly clean around the outside of the fuel line unions.
Temporarily pinch shut the supply line that comes from the transfer pump to the fuel reservoir. See Fig. 4-13 or Fig. 4-14. Place a large container beneath the fuel reservoir for catching fuel.
Fuel pump and filter on cars with CIS, CIS-E, and CIS-E Motronic systems. Pinch shut fuel supply line 1 from transfer pump and remove cap nut 2 to drain fuel.
Fuel pump and filter on cars with Digifant. Pinch shut fuel supply line 1 from transfer pump and disconnect output fuel line 2 to drain fuel.
Disconnect the output fuel line to drain the reservoir. On models with CIS, CIS-E, or CIS-E Motronic, remove the cap nut, the fuel line, and the two sealing washers. On Digifant models, remove the hose clamp and the fuel line.
Fuel will be discharged. Do not smoke or work near heaters or other fire hazards. Keep a fire extinguisher handy.
Remove the three mounting screws from the fuel pump retaining ring and pull the fuel pump assembly from the fuel reservoir.
Moisten the new O-ring with fuel and install it over the fuel pump. Make sure the fuel pump filter screen is clean, then install the pump in the fuel reservoir. Secure the retaining ring with three screws. Tighten the screws evenly, checking to see that the fuel pump is correctly seated.
Reconnect the fuel line and the harness connector. Use new sealing washers and hose clamps as required. On CIS, CIS-E, and CIS-E Motronic models, torque the cap nut to 20 Nm (15 ft. lb.).
Reconnect the negative (-) battery cable. Start the engine and check for leaks.