PeachParts Mercedes-Benz Forum - View Single Post

sokoloff · #1 05-23-2007, 05:12 PM

I'm really dangerous now - my box of parts arrived and I started working on my fuel leak.

Here is the original thread on my situation if anyone cares to review - 606 leaking diesel again. Basically I was positive that my leak was coming from the gasket where the fuel pump mounts to the injection pump. That's where the wetness started. Everything above that was dry. MBDOC mentioned in a message that if the leak was coming form that gasket that it would be black engine oil not clear diesel fuel. I didn't comprehend that, but once I took the fuel pump off, I understood. This fuel pump is very similar to the fuel pump on my ponton that I have removed a number of times and even rebuilt. There is a small cam/lobe from the engine that pushes the rod on the fuel pump creating a suction/vacuum that moves the fuel. The fuel pump has two separate compartments. The compartment mounted against the injection pump is bathed in engine oil. The body of the fuel pump is sealed off from that compartment and has two fuel lines connected to it. See the photos below to see what I'm talking about. The first photo shows where the fuel pump is mounted and you can see the black engine oil in the mounting hole. The other two photos show that the fuel pump is sealed between the fuel side and the engine side. I had planned to replace the O rings, spring and valve in the fuel pump, but since it is a sealed unit and seems to be functioning properly when I depress the rod, I'm leaving well enough alone there.

In addition to fixing my leaking fuel pump gasket which now appears to not be the problem, I also had plans to replace all the O rings with viton and replace all the fuel lines. Today I replaced the fuel shut off O ring, the fuel pump gasket, the prefilter O ring and all of the new fuel line O rings. Tomorrow I hope to tackle the delivery valve O rings.

Hope this helps someone not make extra work for himself. I was kind of wondering why it seemed like I was the only one who seemed to have a leak at that gasket. I still haven't found the real leak, but I'm replacing everything, so that ought to fix it.