Fuel Pump Assembly Installation Details with Fuel Level Sensor (all models)
A - Rear seat frame brackets
Arrow - Fuel pump wiring connector
1. The fuel pump assembly installation details are shown in the illustration, to which all references in the text refer.
2. Empty the fuel tank (see Section Emptying the fuel tank).
Material borrowed from an online resource (MERCEDESMAN)
3. Having completed the procedures of paragraphs 2 through 6 of Section Emptying the fuel tank, remove the cover (84) of the access window to the fuel pump/fuel level sensor assembly.
4. Disconnect the fuel pump wiring connector (arrow).
5. Disconnect the fuel supply (90/12) and return (90/11) lines from the pump assembly; if equipped, also disconnect the fuel line of the stationary heater (90/13) - try to avoid kinking the fuel lines.
Note: If a permanent heater is not installed, do not attempt to remove the connector screw.
6. Using a suitable wrench, loosen the ring nut (89).
Note: The ring nut must be replaced.
7. Carefully remove the fuel pump/fuel level sensor (M3/B4) assembly from the fuel tank, being careful not to bend the sensor float arm.
Attention! The pump and sensor are combined into a single unit that cannot be disassembled!
8. Installation is carried out in the reverse order - lubricate the sealing element (89/2) with oil.