UrS4 Strut pinch bolt size & Bira brake bracket interference

[Fred Munro]

There have been a couple UrS listers who have had the ball joint drop out
while the car has been in motion - one that I recall was at highway speed on
an Interstate. This is guaranteed to ruin your entire day. From what I
recall, in one case the improper bolt had been used. In the other case
someone at the shop had pried open the slot in the strut housing to release
the old ball joint when they were changing the control arm. The tool marks
were still in the slot. This deforms the strut housing and it will never
hold the ball joint again - the strut housing has to be replaced.
This is not an area to fool around with if you don't know the engineering
reasons for some of the design choices. The Bentley states an orientation
for that bolt and there is a reason for that. They don't mention orientation
for many other bolts. Retention of the bolt if the nut falls off is a good
guess, but just having the bolt in the hole won't keep the ball joint in
place. If that bolt loosens off the ball joint will pop out. My guess would
be it has something to do with the way the clamping pressure is put on the
strut housing. In any case, I'd recommend using the correct new bolt and nut
each time it is loosened and orient it per the Bentley.
Chris, removing the BIRA bracket is a PITA, but I'll guarantee it will be
more of a PITA if the ball joint drops out while you are driving the car!

JMHO

Fred Munro
'97 S6

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of dgraber460 at aol.com
Sent: June 2, 2010 11:25 PM
To: talleycm at gmail.com; quattro at audifans.com
Subject: Re: UrS4 Strut pinch bolt size & Bira brake bracket interference


My understanding (which is only hearsay, and my own assumptions) is that a
grade 8 would be more than sufficient, and easily sourced.
My other assumption is that it is head forward so that in the rare case the
nut vibrates off, the bolt will be more likely to stay in place.
Anyone with the true engineering "facts", feel free to chime in.

Dennis 
Denver



-----Original Message-----
From: Chris Talley <talleycm at gmail.com>
To: quattro at audifans.com
Sent: Wed, Jun 2, 2010 9:35 am
Subject: UrS4 Strut pinch bolt size & Bira brake bracket interference


Hello All
Is the strut/ball joint pinch bolt a off the shelf or a dealer only part.
ither way does someone have a spec or a part number.
I had to grind the head off to remove thebolt and strut, because the Bira
racket for the BBK prevent easy extraction,  the Bentley indicates that the
ead should point forward, with the brake bracket it the way that will be
mpossible without removal of the bracket which I am relunctant to do. Why
oes the bolt need to be instalelled in this direction and will it be a bad
dea to install backwards to aid future removal.
TIA,
Chris
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