A faulty fuel pump can cause poor engine performance and hard starting problems. When they fail completely, you may be left with an engine that doesn’t run at all. If you are starting to have problems with your pump or getting a faulty error code for the pump make sure to replace it right away before it leaves you stranded on the side of the road.So here i want to share the guide on how to replace fuel pump for Mercedes Benz C350.
Applies to: C350 (2007-14), C180 (2007-14), C200 (2007-14), C230 (2007-14), C250 (2007-14), C280 (2007-14), C300 (2007-14), C320 (2007-14)
Time: 3 hours
Tab: $220 to $300
Talent: Tools: 8mm socket, large flathead screwdriver, hammer
Parts Required: Fuel pump, fuel pump-sealing O-ring
Hot Tip: Be careful working around gas
Performance Gain: Better running engine
Complementary Modification: Replace fuel filter
Mercedes Benz C350 Fuel Pump Replacement Guide：
Being by opening the fuel filler door and removing the gas cap.This will help relive pressure in the system.
The fuel pump is located under the right side rear seat (red arrow).You will need to remove the lower seat to access it.Please see our article on seat removal:How to Replace Bench Seats for Benz W204
With the lower rear seat and under pad removed you will have access to the cover.Remove the four 8mm bolts holding the cover in place (red arrows).Lift the cover up and off,separating the gasket around the wiring harness.
Clean the duct and debris off the top of the pump and unplug the one connection (red arrow).Separate the other electrical connection.Remove the plug from where it mounts on top of the pump (yellow arrow.)
You will need to remove the locking ring that holds the pump in place in the gas tank.While Mercedes make an expensive tool for doing this,if you are careful you can use a large flathead screwdriver and samll hammer and gently tap the ring back off the tabs.
Use the holes in the other retaining ring and tap evenly around the entire outside of the ring (red arrows).Do not just start hammering away on one spot.Instead,continuously move around the ring.There should be a witness mark on the ring (yellow arrows) that will let you know when it is fully locked (the one on the photograph is unlocked).
Remove the retaining ring note position of the pump in the tank.The large tab on the front of the pump lid must face towards the front of the vehicle (red arrow).
Pull the lid of the pump up and off.There is a sealing ring between it and the tank so it might stick a little.There are two prongs with springs on them (red arrows).These sit inside the pump housing and hold it in place.Disconnect the two electrical connections (yellow arrows)
Unclip the open-ended hose from the pump housing (red arrow).Press in the tab on the other hose fitting and lifting and lift it off the pump (red arrow)
You can now lift the pump out from the tank.Use care that you do not bend or damage the right side level detector (red arrow).The pump housing will be full of fuel so make sure to carefully pour it back into the tank before taking the pump out of the vehicle.Installation is the reverse of removal.Make sure that the lid is positioned and sealed correctly.