prop shaft alignment question

[DeWitt Harrison]

I confess. I wanted to know what the Audi engineers
intended. The parts list shows available spacers in
2mm increments.

So far, the upshot seems to be that is doesn't make a rat's
behind. What were they thinking?

DeWitt


----- Original Message ----- 
From: "Tom Chudzinski" <epiform at msn.com>
To: <six-rs at comcast.net>
Sent: Saturday, September 03, 2005 8:56 PM
Subject: prop shaft alignment question


>
>
> DeWitt writes:
>
> 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 drive shaft 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
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
> Hoping to clear up a little confusion.
>
> What you are looking at when under the car is the engine/transmission,
> subframe/suspension, drive shaft, and rear final drive in their static
> positions with no power applied. <most likely the car is off the ground
> too>
>
> You are an engineer aren't you?  Well, mechanical things don't stay in
> static mode when they are operated in dynamic mode.  From +35 years of
> direct experience as both a repair technician and an engineer, unless
> you have specific evidence that the factory setting(s) is/are wrong and
> have solid reason(s) to think so, (It just doesn't look right from the
> current point of view really doesn't count) don't change it/them, but
> instead, LEAVE IT/THEM ALONE!
>
> Tom Chudzinski
>