Fuel Supply Line: Service and Repair

High Pressure Lines

Special tools, testers and auxiliary items required

• Torque Wrench (5-50 Nm) (V.A.G 1331)

• Socket (T40055)


Loosen the fuel rail and move it slightly. This makes it possible to install the high pressure lines free of tension. The lines must not be bent or under stress. Long term this would cause the line to break.

• The following describes installing new high pressure lines. If reinstalling high pressure lines, which were already removed, then be sure to check the items listed under - item 5 - in the => [ Fuel System Component Overview ] Fuel System Component Overview. The procedure is otherwise identical.

Installing the Separate High Pressure Lines (Cylinders 1 through 4 between the Fuel Rail and the Injector)

- Remove the new high pressure line from its packaging. Remove the plug and immediately install the line between the rail and the injector.

- Make sure the line is installed correctly.

- Tighten the union nuts for the lines completely, by hand without using any tools.

- Proceed the same way with the other lines.

- Tighten the fuel rail bolts. Tightening specification, see - item 15 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.

- Tighten the union nuts on all the lines just installed using the torque wrench (5-50 Nm) (V.A.G 1331) and the socket (T40055). Tightening specification, see - item 5 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.






Installing the High Pressure Line (between the High Pressure Pump and the Fuel Rail) or the Entire Wiring Harness

- Loosen the fuel rail bolts and make sure the it is possible to move the rail, if this was not done before.

- Remove the next fuel line to be installed between the high pressure pump and the rail from its packaging. Remove the plugs and immediately install the line.

- Make sure the line is installed correctly.

- Tighten the fuel injection line union nuts lines completely, by hand, first on the high pressure pump.

- Proceed in the same way with the four other lines, if the entire wiring harness has to be installed.

- Install all three clamps over the fuel line. Make sure they are aligned.






- Install the clamp bolts approximately 3 turns.

- Tighten the fuel rail bolts. Tightening specification, see - item 15 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.

- Tighten the top clamp bolt at the intake manifold to 8 Nm.

- Tighten the union nuts on all the lines just installed using the torque wrench (5-50 Nm) (V.A.G 1331) and socket (T40055). Tightening specification, see - item 5 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.






- Tighten the other two clamp bolts to 8 Nm.

- Position the balance weight - A - to the high pressure lines as shown in the next illustration.

Positioning the Balance Weight





- Press the return line connections carefully over the sealing ring onto the injector (check the sealing ring for damage). The connection must audibly engage. Then carefully press the center piece downward.

- Fill the fuel system. Refer to => [ Fuel System, Filling/Bleeding ] Fuel System, Filling/Bleeding.