Does anyone out there know why this 73 280C has a mechanical fuel pump and an electric pump too? Seems strange to me that an electric pump should be feeding fuel to the mechanical pump. The electric one is definately aftermarket and is not pumping. One wire is grounded on the chassis, and the other runs up the tunnel to the ignition coil. Should I just take this whole mess off and look for a new OE pump, or get another electric one? Also need manuals for this car if anyone has any they want to move along...

Sounds like someone was trying to pressurize their way out of a vapor lock tendency.

I would vote for the new OE pump. They are about $100.

There was a guy on the mercedes-veterans board with an electric who went through some real hassles getting the pressure right. One good thing about the OEM is that it automatically adjusts for engine RPM. AND you don't need to worry about it blowing a fuse and stopping the car.

Chuck

Thanks,
I found a pump on thebenzbin for 25.00, so I think I will try that. The pump for the later model with smog pump is near 100 bucks!

Be sure that you have the plastic spacer plate between the block and the pump. You need two gaskets - one for each side of the spacer.

Do you have hex-key bolts? If so, you will need a "stubby" Allen wrench to get at them.

I will have to check to make sure that I have the spacer. It looks like there are four phillips head machine screws holding the pump on. Kind of strange, no? I will let you know when I pull it. Looks like there were some homemade repairs and parts on this car, but all in all doesen't look as frightening as some that I have owned. I love a challenge.