How You Can Replace the Seals on the Fuel Pump Delivery Valves on a Mercedes Diesel Car Engine
The seals around the fuel pump delivery valves on a diesel car engine can start to leak which can affect how well your engine operates. Replacing the seals is a job most diesel car owners can do by themselves in a couple of hours. If a fuel delivery valve seal is leaking on your car Mercedes diesel car engine, here is how you can replace it.
You Will Need:
- 32-Point Socket
- T-30 Torque Bit
- Ratchet
- Small Socket Extension
- Open Ended Wrenches
- Pick Tool
- New Copper Seal
- New Rubber O-Ring
Remove Fuel Hose Line
The fuel delivery valves are on the top or side of the engine where the manifold cover is located. You need to unscrew the leaking valve from the manifold cover for the fuel injectors. Use a 14 mm open-ended wrench to loosen and remove the main nut connecting the fuel hose line to the top of the delivery valve. You want to turn the nut counterclockwise to loosen it. Detach the hose line from the top of the valve.
Remove Holding Ring
There is a holding ring at the base of the valve where it meets the manifold cover. You need to remove the holding ring. Use a T-30 torque bit to remove the screw securing the holding ring to the manifold cover. The holding ring will slide up and over the valve so you can remove it.
Remove Delivery Valve
Place the 32-point socket over the delivery valve. The points in the socket will interlock with the ridges on the outside of the valve so you can unscrew it. You will need to put a small socket extension on the ratchet so you can reach the valve and turn it. Turn the valve counterclockwise to loosen and remove it. There is a loose compression spring inside the valve that will stay on the top of the fuel injector when you take out the valve. Be careful to not knock the spring over and lose it.
Replace Seal and O-Ring
The rubber O-ring is located on the bottom threads of the valve. Remove the O-Ring and slide a new one onto the threads. You also need to pick up the compression spring so you can get to the copper seal that is also on top of the fuel injector. You should use a pick tool to remove the copper seal. A pick tool has a small pointed end that is good for reaching into tight spots. Place the new seal in the same place as the old one was located.
Put Everything Back Together
Set the compression spring back into place over the top of the copper seal and screw the delivery valve back into position. Put the holding ring back over the valve and screw it in place. Reconnect the fuel line to the top of the delivery valve. Start the car and let it run to make sure the injector is working well and there aren't any more leaks.