1. Safety Precautions:
- Disconnect the vehicle's battery to avoid any electrical accidents.
- Engage the parking brake and chock the wheels to prevent the car from rolling.
2. Locate the Fuel Pump:
- The fuel pump on the Volvo 850 is located under the rear seat.
- Flip the seat cushions forward and remove the plastic covers to access the fuel pump assembly.
3. Disconnect Fuel Lines:
- Locate the fuel lines connected to the fuel pump.
- Use a fuel line disconnect tool or pliers to carefully disconnect the fuel lines.
- Place a container underneath to catch any spilled fuel.
4. Remove the Fuel Pump Assembly:
- Once the fuel lines are disconnected, remove the bolts securing the fuel pump assembly to the vehicle.
- Carefully lift the fuel pump assembly out of the tank, taking care not to damage the fuel level sender unit.
5. Transfer the Fuel Level Sender Unit:
- The fuel level sender unit is attached to the original fuel pump.
- Carefully remove the sender unit from the old pump and transfer it to the new fuel pump.
6. Install the New Fuel Pump:
- Place the new fuel pump with the attached fuel level sender unit back into the fuel tank.
- Secure it with the bolts removed earlier.
7. Reconnect Fuel Lines:
- Reconnect the fuel lines to the fuel pump assembly by pushing them in until you feel a click.
8. Test the Fuel Pump:
- Turn on the ignition switch to the "ON" position without cranking the engine.
- Check if the fuel pump runs for a few seconds and then turns off.
- If the fuel pump works as expected, proceed to the next step.
9. Replace the Seat and Covers:
- Reinstall the plastic covers and flip the rear seat cushions back into place.
10. Start the Engine:
- Start the vehicle. Let it run for a few minutes to ensure that the fuel pump is functioning correctly.
11. Reconnect Battery:
- Reconnect the battery terminal.
12. Check for Leaks:
- Look under the vehicle for any fuel leaks around the fuel pump assembly. If none detected, the replacement is successful.
Remember that working with fuel systems can be dangerous, so proceed cautiously following all safety precautions. If you are uncomfortable with any step, consider consulting a professional mechanic or refer to the vehicle's service manual for specific instructions related to your Volvo 850 model.
