Replacing Fuel Pump In Gl450: Step-By-Step Guide

If your 2008 GL450 has stalled, you may need to replace the fuel pump and sending unit. This can be done at a dealership, but will cost upwards of $2300. It is possible to do this yourself, but it is a complex process that requires specific tools and knowledge. The first step is to remove the rear seat flaps and bottom covers, then the rear seats themselves. You will then need to remove the seal and lift the cap to access the fuel pump. Before removing the fuel lines, you should start the engine and wait for it to run out of fuel to minimise spillage. You will then need to remove the locking ring and lift the fuel pump out, taking care not to tilt it more than 45 degrees to avoid spilling fuel from the pump reservoir. Insert the new fuel pump, ensuring the rubber gasket has a tight fit, and replace the locking ring. Finally, snap the fuel lines back into place, start the engine, and use body sealant to seal the cap.

Remove rear seat flaps and bottom covers

To remove the rear seat flaps and bottom covers of your 2008 GL450, follow these steps:

First, locate the flaps of the rear seats. These are found in the rear passenger side of the vehicle. There are no screws holding the flaps in place, just tabs. Be careful when releasing the tabs as they can easily break. There are detailed instructions on how to do this in the PDF provided in the link above.

Once the tabs are released, and the flaps removed, you will be able to see the under surface of the cover. Next, you will need to unscrew the rear seats. There are two hex nuts and several torx bolts holding the seats in place. Be sure to disconnect the SRS cables; there is one cable for each seat.

Now, you can 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 access the driver's side. Fold the floor mat on the driver's 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 be able to see the top of the fuel pump. Take a picture to document the alignment of the pump connections.

Disconnect SRS cables

To disconnect the SRS cables, follow these steps:

• Disconnect the negative battery cable.
• Remove the driver-side kick panel.
• Remove the driver-side floor console.
• Remove the SRS control module from the floor console.
• Disconnect the SRS control module electrical connectors.

Remove rear seats

To remove the rear seats in your 2008 GL450, follow these steps:

Begin by opening the rear doors and locating the levers or handles at the base of the seatback, near the floor. These levers will release the seatbacks, allowing them to fold forward. If you have headrests, remove them by pressing the button and lifting them out. Now, locate the bolts or fasteners that secure the base of the rear seat to the vehicle floor. These are typically visible once you fold the seatback forward. You may need to remove any plastic covers or panels that conceal the bolts.

Use the appropriate tool to loosen and remove these bolts, and set them aside in a safe place for reinstallation. With the bolts removed, carefully lift the rear seat outward and upward. The seat may be heavier than expected, so take care not to strain yourself. There may be additional wiring or connectors attached to the seat, typically for features like seat heaters or entertainment systems. Disconnect these carefully, noting their placement for reinstallation.

With the bolts removed and any connectors detached, you should now be able to lift and remove the rear seat from the vehicle. Place it on a clean, soft surface to avoid damage. If you need to remove the rear middle seat, it is typically secured in a similar fashion. Look for bolts or fasteners at the base of the middle seat and remove them, following the same process as outlined above.

Once all the bolts are removed, carefully lift and remove the middle seat. It may have additional connectors for features like armrest controls or climate controls, so take care to detach these as necessary. With the rear seats removed, you will have access to the fuel pump area, and you can proceed with the next steps in the fuel pump replacement process. Remember to keep all bolts and connectors organized for easy reassembly when your fuel pump replacement is complete.

Remove seal and lift cap to access fuel pump

To remove the seal and lift the cap to access the fuel pump, you will first need to locate the access hole. This can be 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 by sealant only.

To remove the seal, you will need to carefully pry it off with a flathead screwdriver or similar tool. Be careful not to damage the cap or the surrounding area. Once the seal is removed, you can lift the cap. It should come off fairly easily, as it is only held in place by the sealant.

With the cap removed, you will now have access to the fuel pump. Before proceeding, it is recommended to take a picture to document the alignment of the pump connections. This will be helpful when it comes time to reinstall the new fuel pump.

Now, you can continue with the next steps of the fuel pump replacement procedure. Be sure to follow all safety precautions and refer to a qualified mechanic or repair manual for further guidance if needed.

Disconnect fuel lines and power cable

Disconnecting the fuel lines and power cable is a crucial step when replacing the fuel pump on your 08 GL450. Here is a detailed guide to help you through the process:

Before you begin, ensure you have placed towels around the work area to absorb any fuel spills. This step is important to minimize the inhalation of fuel vapors, which can be dangerous.

Now, to disconnect the fuel lines and power cable:

• Start the engine and wait 5-10 seconds until the engine runs out of fuel and stalls. This is important to ensure that the fuel lines are not pressurized when you disconnect them.
• Carefully disconnect the fuel lines. Push the line and press the tabs on each side with your fingers to remove it. There will be two tabs to press on each side of the fuel line connector.
• Be cautious as the fuel line in the center (feeding line) is still pressurized and will have fuel remaining in it. Collect the fuel into a cup immediately after disconnecting the line. Fuel will come from the line, not the pump.
• Once the fuel lines are disconnected, locate the power cable. It should be plugged into the top of the fuel pump.
• Unplug the power cable from the fuel pump. This will cut the power supply to the pump.

At this point, you have successfully disconnected the fuel lines and power cable from your 08 GL450's fuel pump. Remember to work cautiously and refer to a trusted repair manual or a mechanic if you are unsure about any steps. Always put your safety first when working on your vehicle.

Frequently asked questions