Oil drips from new W111 fuel pump

[ScooterABC]

My much-loved mechanical lever prime fuel pump has failed on my 63 220S and so I have replaced it. First with a Meyle, then with an MTC. Both leak oil from the same spot. Am I doing something wrong??? The Meyle came with a spacer block, 2 O-rings for the spacer block, and one paper gasket. When I installed that the spacer block cracked because the compression of the O-ring wasn't sufficient to keep it from stressing at the bolt points and it cracked the block around the O-ring. Vendor sent me another spacer block and I installed without the O-ring between the pump and the spacer so that the pressure towards the engine would be even on the O-ring. Great, except the pump (Meyle) leaked from the seam.

So I told vendor and was sent a replacement, mistakenly the MTC equivalent. Fine, whatever, so I installed it with no O-rings, 2 gaskets, and the spacer block. It leaks from the same place.

Is my problem something I'm doing wrong, or are they cheap fuel pumps or....???

[ScooterABC]

To make matters worse, I thought that the Meyle pump (same model) that I installed in my parts car to get it running (a 1960 220S) was not leaking. Upon closer inspection this evening I discovered that it too leaks, it was just not noticed because I have only run the engine a little bit. And it is probably leaking less.

Also it appears that none of the 3 NEW pumps are leaking from the crimped seal, instead they are leaking from the little hole that is part of the design. See attached.

I'm at a loss for what to do. This can't be right.

Scott

[mosu]

For what it's worth, I had the exact same problem. First Meyle pump leaked from the weep hole. The replacement doesn't leak so far.

When I removed the leaky pump, it appears that it was sucking oil past the plunger seal and pissing it out the weep hole. I suspect that there should be a functional seal around the plunger that may have gone bad from sitting on shelves.

[ScooterABC]

I talked to Tom at the Classic Center. He gave me an entirely different part number and is sending it to me. We'll see what I get. EPC disagrees with what he is telling me but I'm going to try it anyway.

[Carpenterman]

Sorry for your hassle. I tried one of those pumps (branded Vaico) on my '66 230 and it did the same thing. I pulled it, blocked off the engine, and installed an electric pump.

I think they are just junk.

[ScooterABC]

the Mercedes pump from the classic center looks almost exactly like the aftermarket pump, right down to the casting. However, it does not leak. So I have two aftermarket ones to return.