Vacuum system changes

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Jun 22, 2003 | 09:43 PM

3Sq

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Vacuum system changes

It appears that the vacuum schematic for the AFC 12v (or 96/97 A4) is different than the one for the earlier 12v.

I noticed that the vacuum reservoir and one-way check valve is used for the intake path switch in later 12v's, and for the EGR valve in earlier 12v's. Why? Any other differences?

Also, Audi has a superceded part (number) for the vacuum reservoir. Why? I'll post any obvious differences when I receive the part this week.

Thanks,
3Sq
96 A4QM

Jun 22, 2003 | 10:26 PM

moribundman

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That's how it is on my '96 AFC (Same old vac diagram - if you've seen it, don't bother!)

I've noticed differences in the arrangement and routing of vac hoses even within the same model year. I can't help you with the differences, but I can show you my car's vacuum diagram.

<img src="http://home.earthlink.net/~triphibious2/96_vacuum.jpg">

Jun 23, 2003 | 04:47 AM

VAP

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The new superseded part number vacuum reservoir now features a....

thermal wrap of very thick aluminum foil around it's lower half. Looks like an inverted "Jiffy-Pop" container). I assume to prevent the vacuum line port stem coming from the reservoir from cracking/breaking away with the vacuum line attached to it. Thats what happened to mine and when I ordered the old part number I got the new superceded part wrapped in foil around it's lower hemisphere.

Jun 23, 2003 | 07:16 AM

AudiMick

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From: Redmond WA

Did you update it, it looks new and improved!

Jun 23, 2003 | 07:31 AM

moribundman

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It's the same! ;-)

Jun 23, 2003 | 08:17 AM

3Sq

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Disintegrated hose

That's what happened to mine also. The braided vacuum hose disintegrated and the reservoir nipple broke off while trying to remove the hose.

The only other vacuum hose that was in that bad condition was the tb-plenum hose.

3Sq

Jun 23, 2003 | 08:24 AM

3Sq

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Too bad Bentley or Chilton do not...

...depict and describe the differences. The changes may be a design improvement.

BTW, the setup in my 96 A4QM (11/95 build date) is as yours.

Thanks,
3Sq