For models 463.333 (M628)
Attention! Self-locking fasteners must be replaced!
Valve installation details (M628)
1, 2, 3 - Fuel system pressure lines; 4 - Hollow bolt of the nipple connection; 4a - Nipple connector; 4b - Sealing rings; 5 - Screw; 6 - Fuel return line; 70 - Fuel filter; 21/7 - Valve assembly; B4/6 - Fuel line pressure sensor; Y74 - Pressure Regulator Valve
1. Turn off the ignition.
2. Open the hood and fix it in a vertical position.
3. Remove the air cleaner (see Section Servicing air intake tract components).
4. Remove the oil filler neck trim panel.
5. Remove the fuel filter (70).
6. Disconnect the electrical wiring from the fuel line pressure sensor (B4/6) and the pressure regulating valve (Y74).
7. Disconnect the fuel pressure lines (1, 2 and 3) - immediately seal the open ends of the lines/fittings, collect traces of spilled fuel, prepare replacement seals.
8. Unscrew the hollow bolt (4) and remove the nipple connector (5).
Attention! Sealing rings (4b) must be replaced without fail!
9. Unscrew the mounting bolts (5) and remove the valve assembly (21/7) complete with the return line (6) connected to it.
10. Disconnect the return line (6) from the valve assembly (21/7) - prepare a replacement sealing ring.
11. Installation is carried out in the reverse order - do not forget to replace the sealing elements.
Note: The final tightening of the union nuts of the fuel pressure lines (1, 2 and 3) should only be carried out after tightening the bolts (5).
12. Start the engine and check the fuel system components for signs of developing leaks. Finally, clear the memory of the on-board diagnostic module (see Chapter Engine electrical systems).