UrS4 Strut pinch bolt size & Bira brake bracket interference

[Cody Forbes]

Actually it's not in double shear, it's not in shear at all in normal  
use. The bolt is used to clamp the pinch area to hold the ball joint  
pin. That means it's purely under tension. I suppose that if/when it  
comes loose the relief in the ball joint could be considered to be  
putting it in shear, but it shouldn't be loose.

-Cody (mobile)

On Jun 4, 2010, at 5:34 PM, Mark Rosenkrantz  
<speedracer.mark at gmail.com> wrote:

> Proper fit is the key.  Having the correct thread length is critical  
> to
> maximize the contact area.  The bolt is in double-shear so I doubt the
> forces would require any exotic steel.
>
> ARP makes excellent fasteners, but having a custom fabricated  
> mechanical
> fastener for this application does seem overkill when the only  
> failure mode
> of the factory (inexpensive) bolt is due to corrosion.  And that only
> manifests itself during removal.  Personally, I reinstall the new  
> fastener
> with anti-sieze on the wheel bearing housing contact areas.
>
> Mark Rosenkrantz
>
> On Thu, Jun 3, 2010 at 7:35 PM, Chris Talley <talleycm at gmail.com>  
> wrote:
>
>> I ordered the parts from the deal for  $ 2 a piece.
>>
>> As far as outsourcing I thought there might be a better/higher
>> quality choice for the application, there are aerospace and other  
>> ultra
>> high
>> quality automotive fasteners like ARP that offer the same  
>> specifications,
>> and usually have very good technical support and a premium price.
>>
>> The design on the URS4 ball joint incorporates a groove to retain  
>> the ball
>> joint in case the fastener loosens.
>>
>> Chris
>> .
>> On Thu, Jun 3, 2010 at 9:25 AM, <dgraber460 at aol.com> wrote:
>>
>>> My reason for "qualifying" my remarks is evident.
>>> My experience is with the URQ struts, and the ball joint for them is
>>> grooved in such a way that if the bolt is the correct diameter and
>> present,
>>> the joint cannot come out.
>>> I have seen a 928 loose a BJ while moving and agree it is _not_ an  
>>> area
>> to
>>> try to substitute or save money.
>>>
>>> Dennis
>>> Denver
>>>
>>>  -----Original Message-----
>>> From: Fred Munro <munrof at sympatico.ca>
>>> To: dgraber460 at aol.com; talleycm at gmail.com; quattro at audifans.com
>>> Sent: Thu, Jun 3, 2010 7:09 am
>>> Subject: RE: UrS4 Strut pinch bolt size & Bira brake bracket  
>>> interference
>>>
>>> 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<
>> 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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