Replacing The Fuel Pump In Your 2008 Mb R350

Replacing the fuel pump in a 2008 Mercedes-Benz R350 is a complex process that requires specific tools and expertise. The fuel pump is responsible for delivering fuel from the tank to the engine, and a failing pump can cause engine power loss or prevent the car from starting. While it is possible to replace the fuel pump yourself, it is not recommended due to the risk of fire. The average cost for a professional fuel pump replacement in a 2008 R350 ranges from $631 to $2229, including parts and labour.

The process of replacing the fuel pump involves multiple steps, including:

- Disconnecting the battery to reduce the risk of fire.

- Gaining access to the fuel pump, which may require removing an access cover or lowering the fuel tank from the vehicle.

- Disconnecting fuel lines, EVAP system hoses, and electrical connections to the pump.

- Removing the old fuel pump and installing the new one, ensuring proper alignment of fuel lines and a tight fit for the rubber gasket.

- Re-establishing all hoses and electrical connections, and refilling the fuel tank.

- Testing the engine to ensure there are no fuel leaks and that the problem is resolved.

Disconnect the battery to reduce the risk of fire

Disconnecting the battery is the first step in replacing the fuel pump of a 2008 MB R350. This is a crucial safety precaution to reduce the risk of fire when working on the fuel system.

The fuel system in a car is highly flammable, and disconnecting the battery will prevent any power from being sent to the fuel pump, reducing the risk of sparks or an explosion. It is essential to take all necessary precautions when working with the fuel system to ensure safety.

Before disconnecting the battery, it is important to identify the type of fuel pump in your vehicle. In some cars, the fuel pump is located inside the fuel tank, while in others, it is located outside the tank. If the pump is inside the tank, an access cover will need to be removed to reach it. In some cases, the fuel may need to be drained before removing this access panel.

For the 2008 MB R350, the fuel pump is located inside the fuel tank. To disconnect the battery, locate the negative terminal, which is usually marked with a "-" symbol. Use a wrench or socket to loosen the nut or bolt that secures the cable to the terminal. Be careful not to let the wrench touch any metal parts of the car, as this could cause a spark. Once the nut or bolt is loose, carefully remove the cable from the terminal.

After disconnecting the battery, it is important to secure the cable to prevent it from accidentally touching the terminal and causing a spark. You can use electrical tape or a cable tie to secure the cable. Now it is safe to proceed with the next steps of replacing the fuel pump.

It is important to note that working with the fuel system can be dangerous, and it is recommended that this job be left to professionals unless you have sufficient auto repair experience. Always take the necessary precautions to ensure your safety when working on any part of your vehicle.

Remove the rear seats and rear seat bottom covers

To remove the rear seats and rear seat bottom covers of your 2008 MB R350, follow these steps:

First, remove the flaps of the rear seats. You can find the location of the access site in the first picture of the instruction manual. Next, remove the rear seat bottom covers. There are no screws, just tabs. Releasing the tabs is the most challenging step as they break easily. You can refer to the detailed instructions in the provided PDF for this step.

Now, unscrew the rear seats. There are two hex nuts and several torx bolts. Disconnect the SRS cables; there is one for each seat.

Then, remove the 40% seat (rear passenger side) from the car. The 60% seat is very heavy, so just slide it to the location of the 40% seat so that you can work on the driver's side. Fold the floor mat (driver-side corner) and you will see a round cap covering the access hole. This cap is attached to the body by sealant only. Remove the seal and lift the cap. You will now see the top of the fuel pump.

Take a picture to document the alignment of the pump connections. You can refer to the second picture in the manual for this.

Disconnect the SRS cables

Disconnecting the SRS cables is a complex process that requires a lot of care and attention to detail. Before you begin, make sure you have the right tools and safety equipment.

To disconnect the SRS cables, you will need:

• Safety glasses
• Gloves
• A flat-head screwdriver
• A Phillips-head screwdriver
• A wrench
• A wire cutter
• A wire stripper
• A soldering iron
• A soldering gun
• Electrical tape
• A multimeter
• A new SRS cable

Step-by-step guide to disconnecting the SRS cables:

• Disconnect the battery. Before you begin working on your car, disconnect the battery to prevent any electrical shocks or short circuits.
• Remove the steering wheel. Use a wrench to remove the steering wheel nut, then lift the steering wheel off the steering column.
• Remove the driver's side knee airbag. Remove the screws holding the knee airbag in place, then disconnect the electrical connectors.
• Remove the driver's side door trim panel. Remove the screws holding the door trim panel in place, then carefully lift the panel off the door.
• Disconnect the SRS cables. Use a flat-head screwdriver to pry open the electrical connectors, then use a wire cutter to cut the cables.
• Strip the wires. Use a wire stripper to strip about 1/2 inch of insulation from the ends of the wires.
• Solder the new SRS cable. Use a soldering iron and soldering gun to solder the new SRS cable into place. Make sure the wires are securely connected, then use electrical tape to secure the connection.
• Test the SRS system. Reconnect the battery, then turn on the ignition. The SRS light should come on for about 5 seconds, then turn off. If the SRS light stays on or comes on while driving, use a multimeter to test the circuit for continuity.

Remove the seal and lift the cap to access the fuel pump

To remove the seal and lift the cap to access the fuel pump, you will first need to locate the fuel pump access hole. This is found by folding the floor mat on the driver's side corner. You will see a round cap covering the access hole. This cap is attached to the body of the car by a sealant.

To remove the seal, you will need to carefully pry it off with a flat-tip screwdriver or similar tool. Be careful not to damage the surrounding area. Once the seal is removed, you can then lift the cap. Underneath the cap, you will see the top of the fuel pump. Take a picture at this point to document the alignment of the pump connections.

The next step is to unplug the cable, which is the power line to the pump. Then, you can start the engine and wait 5-10 seconds until the engine runs out of fuel and stalls.

Now you can access the fuel pump and proceed with the replacement.

Disconnect the fuel lines and collect the fuel

Disconnecting the fuel lines and collecting the fuel is a crucial step in replacing the fuel pump of a 2008 MB R350. Here is a detailed, step-by-step guide on how to safely and effectively complete this task:

Step 1: Prepare the Work Area

Before beginning any work on your vehicle, it is important to take the necessary safety precautions. Fuel is highly flammable, so ensure the work area is well-ventilated and free of any potential ignition sources, such as lit cigarettes or open flames. Place several towels around the work area to absorb any spilled fuel. Keep a fire extinguisher nearby in case of emergencies.

Step 2: Access the Fuel Pump

Locate the fuel pump, which is usually found inside the fuel tank. In the case of the 2008 MB R350, you will need to remove the rear seat flaps and bottom covers to access the fuel pump. Be careful when releasing the tabs as they can easily break.

Step 3: Unplug the Power Cable

Once you have accessed the fuel pump, unplug the power cable that supplies electricity to the pump. This will prevent any accidental activation of the pump during the replacement process.

Step 4: Start the Engine and Let it Stall

Turn the ignition key to start the engine. Wait for 5-10 seconds until the engine runs out of fuel in the lines and stalls. This step is important to relieve pressure in the fuel lines and prevent fuel spraying when the lines are disconnected.

Step 5: Disconnect the Fuel Lines

This step requires caution as the fuel lines are still pressurized and contain fuel. Locate the feeding line, which is the fuel line in the center. Using your fingers, press the tabs on each side of the line and remove it. Fuel will start to come out of the line, so be ready to collect it in a suitable container. Place the collected fuel in a safe area, away from any potential ignition sources.

Step 6: Manage Spillage

It is normal for some fuel to spill during this process. Use the towels you placed earlier to absorb the spilled fuel and minimize the risk of inhalation of fuel vapors. Remember to work quickly but carefully to reduce the risk of fuel spillage.

By following these steps, you can safely disconnect the fuel lines and collect the fuel when replacing the fuel pump in your 2008 MB R350. Always exercise caution when working with fuel and refer to a professional mechanic or the vehicle's repair manual if you have any doubts or concerns.

Frequently asked questions