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Last time I rebuilt my engine I spent a bunch of time rebuilding my fuel/vacuum pump. The fuel pump works great but the vacuum pump side (Lower half) never seemed to do anything. Now I find its been pumping crankcase oil into the #6 intake manifold all this time.

Lovely.

Today we're putting this all back together and one of the things on the list is to fix the leaking vacuum pump. We pulled it apart and can't figure out what was going wrong. Where was the oil coming from? And, how in the world was this supposed to work anyway?

I'd really like to get the vacuum system working again. Its so Rube Goldberg, it'd be great if it actually worked. So if anyone has any experience with these things, Please! I'd love to have whatever pointers possible.

Thanks!

-jim lee

Sounds like the diaphragm has failed, try looking closely at it to see if it has any indication of rips or perforation.

That was the first thing I thought as well. But it looks like there's vacuum on both sides of the diaphragm. The oil has to get in somewhere else.

Jim,
Our truck did the same thing, but only if it was at an angle that the oil was able to enter the pump (steep hill). I suspect the seal for the diaphragm's driving rod was the culprit. When we rebuilt the pump it looked none to healthy. Keep an eye on the pivot pin holes too, we had an oil leak there too.

Andy

Yeah, I'm working on it today. It looks like the vacuum shaft seal actually fell out. And that would explain everything if this is the case. Actually should be reassembling it as I type, but I'm feelin' really lazy. Uggh! Gotta' go do this.

-jim lee