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Play in Vacuum Pump shaft

Posted: Wed Jun 07, 2017 5:18 pm
by oren_hc
1982 Jetta 1.6NA

I'm troubleshooting some oil pressure issues and noticed the shaft on the vacuum pump has maybe 1/2" of play in it. Is that normal?
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I'm new to this forum, thanks for your help!

Re: Play in Vacuum Pump shaft

Posted: Sat Jun 10, 2017 5:32 pm
by TylerDurden
That doesn't look like quite 1/2", but it looks a bit more than the 1/8 or 3/16 that the spare in my parts pile has.

I don't know much about the early vac pump and the Bentley I have doesn't say anything about that length, so no telling what the limits are.

I'm gonna guess that the rotation of the IM shaft pushes the gear against the pump, so you needn't worry much. If you are curious/concerned, you could take off the shaft cover and make sure the circlip and washer are on the end of the shaft (so it doesn't fall into the engine).

Maybe one of the others here has more info.

Re: Play in Vacuum Pump shaft

Posted: Tue Jun 13, 2017 12:14 am
by Fatmobile
That doesn't look bad.
It looks bad when the gear has worn into the bronze bushing around the shaft in the bottom of the pump.
As it wears upward; it pulls away from the oil pump and creates a ramp where they meet. Pushing them apart even harder.

That can disengage if it wears into that bushing too much.

You know there is an oil seal inside the bottom of the gear right? Seals around the oil pump shaft.

Re: Play in Vacuum Pump shaft

Posted: Tue Jun 13, 2017 12:22 am
by greg lousy
If the play your talking about involves rotating the pump shaft and having the gear not engage until you turn it a little, thats normal. Theres room where the shaft engages with the gear so that the vacuum pump can slide in and engage without being in one exact position

Re: Play in Vacuum Pump shaft

Posted: Tue Jun 20, 2017 11:27 am
by oren_hc
Thanks for the info.

The play i'm talking about it just up and down on the shaft. If that oil seal isn't in the bottom of the vacuum pump shaft is there any chance that could cause oil pressure issues under acceleration?

Re: Play in Vacuum Pump shaft

Posted: Tue Jun 20, 2017 2:17 pm
by oren_hc
And where can I track down that seal?

Re: Play in Vacuum Pump shaft

Posted: Tue Jun 20, 2017 3:19 pm
by Fatmobile
I think I have to go to the dealership for that seal.
It's probably still there but the factory seal is black and probably brittle so you think it's metal.
The new ones are green.