I found the same thing. Mine was new and it leaked fuel and oil. A replacement did the same thing. I finally gave up and went back to the single unit.
I learned TODAY that this can be an issue- in fact, that's why I'm on here tonight looking for a thread about what he describes.
A mechanic I trust very well told me in no uncertain terms that I should NOT use a mechanical fuel pump on my truck because those older style pumps have had problems with the diaphragm wearing out and allowing fuel to leak into the oil... often with catastrophic results. My first response was "they ran with mechanical pumps for a LONG time, why is it a problem now?" His pump was also a combo and it did that to him and so he was scared of using anything but an electric pump after that.
What is the opinion of the experts in this forum about those older designed pumps? I have a NOS combo that I would HATE to have to give up on. Should I just have it rebuilt w/ new diaphragms in case the others have dried out over 60 years (a possibility I expected from the start!)
