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1981 240D California version
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169 Posts
Discussion Starter #1
I recently rebuilt my piston style vacuum pump along with a few other things. After the rebuild, I was only pulling about 15hg of vacuum from the brake booster with the outlets plugged. I took the pump off again and thinking that I must have rebuilt it wrong. I'm pretty sure I got it right - the only instructions I had to go on was a pictorial somewhere on the web that I got a link to from here.

I guess one thing that I didn't really take much notice to was the amount of oil in the vacuum pump. Should the inside of the pump have a lot of oil in it?

I read a post about the shut off valve diaphram being torn and sucking in oil from the IP. When my car was last running, it was starting to (every once in a while - NOT every time) have trouble shutting down. Connection? Anyone? I don't want to pay $100 for a new valve unless I know it's bad..
 

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Registered
1981 240D California version
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169 Posts
Discussion Starter #2
So I took off the shut off valve and it is definitely holding vacuum. The gaskets were very oily and I'm ordering new ones. I don't know if this makes any difference..
 

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2013 MINI Copper S Clubman, '84 300CD-weekend car
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10,152 Posts
Does the brown vac line connected to it have any oil inside it?
I had a shut off valve shut the engine down when I hooked a mity-vac to it, yet there was oil dripping from the ignition switch. I replaced the valve, problem solved.
I have the new style pump, I think, I get around 24Hg.
 

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Registered
1981 240D California version
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169 Posts
Discussion Starter #4
Ok, so it is not the shut off valve..
I took the pump back out and I just checked to see if I did everything right. Put it back on and with the same result. The tutorial Rebuilding the vacuum pump on the 617.952 is missing one photograph. At the end he wrote:

"With the piston in replace the three check valve seals, then the valves: note that the two go ‘crown down’ and the one goes ‘crown up’. Then place the new sealing ring around the top, fitting it around everything so that it does not get crimped."

I guess I should have paid more attention when I took it apart, but here is my question -

Imagine the little valves that are under the cover as the shape of cereal bowls. There is definitely one side that curves down so that it could resemble a bowl if you use your imagination. What side of the bowl would be crown up and crown down? Is it the top (in which the cereal would go) or the bottom (where it would sit on the table)?

I have one bottom up and two top up.

I hope that makes sense. The photo that is missing is this exact one..
 
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