prop shaft alignment question

[DeWitt Harrison]

Hi Fred. Thanks for weighing in on this one. The advice has
been this way and that, yet all of it seemed reasonable.

I did manage to sort out the fore/aft center bearing location issue. I
just got worried when the new "straight" alignment varied so much
from the original. Part of the problem is the new tranny and engine
mounts have raised all that stuff while the center bearing rubber
mount is still its same, saggy old self.

Anyway, "straight" makes the most sense to me although, aparently,
it's not all that critical. My BMW 635CSi from the same era and
with the same driveshaft layout explicitly says that the driveshaft
should be in alignment (as opposed to 'drooped' by some angle).

DeWitt

----- Original Message ----- 
From: "Fred Munro" <munrof at sympatico.ca>
To: "DeWitt Harrison" <six-rs at comcast.net>; "Quattro List"
<quattro at audifans.com>
Sent: Thursday, September 01, 2005 7:41 PM
Subject: RE: prop shaft alignment question


> Hi DeWitt
>
> The fabled Audi alignment tool is straight in both planes (vertical and
> horizontal).
>
> The rubber centre bearing mounts tend to sag with age, so re-aligning an
old
> shaft may require changing the original spacers. Make sure you get the
> fore-and-aft spacing right if you didn't mark the original mount position.
> Move the shaft forward as far as it will go; mark the mount position. Move
> it back as far as it will go; make another mark. Install the mount mid-way
> between both marks.
>
> Fred Munro
> '94 S4
>
>
> -----Original Message-----
> From: quattro-bounces at audifans.com
> [mailto:quattro-bounces at audifans.com]On Behalf Of DeWitt Harrison
> Sent: September 1, 2005 10:51 AM
> To: Quattro List
> Subject: prop shaft alignment question
>
>
> I had the drive shaft out of my 5kcstq to replace motor
> and transmission mounts. I didn't closely inspect the
> alignment of the front and rear halves of the shaft before
> doing so but I vaguely recall that the shaft seemed to droop
> in the middle.
>
> After reinstall, working from the assumption that the
> shaft should be perfectly in line, I adjusted the thickness
> of the spacers that sit between the drive shaft center bearing
> and the body accordingly. I ended up with 0 mm (no
> spacers) from the original 10 mm spacers.
>
> The driveshaft is definitely straight but is that what I want?
> Although straight, the center bearing does sit a little low
> within its rubber support. Almost every 5kq drive shaft I
> have looked at since seems to droop in the center.
> My car is not drivable so I can't just try it out.
> Is the fabled Audi alignment tool straight? Or does it
> intentionally introduce a bit of droop into the system?
>
> The guys at the shop say they always just reinstall the
> original spacers after any work and there's never a
> problem.
>
> Once again confused in Boulder.
>
> DeWitt Harrison
> '88 5kcstq
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