[s-cars] BBK issue

[McCall, Randy]

Think I'll shorten the string a bit and report on my most recent
efforts.  Swapped rotors and brackets after scrupulously cleaning both
the pad surface and rotor with clean rags and brake fluid.  Drove 27
miles afterwards to test things out, and no noise so far.  What does
that prove?  Who da heck knows at this point - perhaps I had some
contamination on the rotor that was tending to drag the pad?  This was
with practically new parts, so no issues on bedding used pads on used
rotors for my setup; stock Textar pads, vibration dampers, machined
brackets from 034, all da good sh*t.  Damn Porsches run this stuff
without whinin' like a bitch, I should be able to as well!

Now I just gotta burn off that smell of the dead animal that was
sleepin' in the road this weekend which my somewhat low car sort of
grazed over (loudly) and which has been described as "burned pizza
smell" when exiting the passenger rear door....  Got the power washer
out before my test drive. If it isn't one damn thing, its another.

-Randy  

 


Date: Mon, 07 Jul 2008 21:01:51 -0400
From: Mike Fitton <rfitton at vt.edu>
Subject: Re: [s-cars] BBK issue
To: jpb3 <jpburns3 at gmail.com>
Cc: jpb3wvu at yahoo.com, "s-car-list at audifans.com"
	<s-car-list at audifans.com>
Message-ID: <4872BC7F.8070203 at vt.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Yeah man, similar symptoms here.  Identical setup also.  I think what 
you're describing is what I have come to describe as a "groan."  It 
happens frequently at times of low speed and no pedal application.  It's

more likely to happen if I'm actually turning the wheel either
direction.

Speaking of hoping, I'm hoping it's not a big deal, but I've had the 
setup and the symptom for over a year now with no tangible difficulties 
whatsoever.  I've come to believe it's one of two things.  More likely 
to me, the DS2500 just makes some weird sounds in general and it's 
nothing to worry about.  In the back of my head is the possibility that 
it has something to do with the rotor offset being 1mm off compared to 
the RS2 package.  Both theories are easy to test, but for one reason or 
another I haven't gotten around to other.  I'm willing to tolerate the 
noise in exchange for sheer athleticism of the package, and that 
overrules the fact that I don't have an easy way of milling down the 
brackets that precisely.  I'd reluctantly consider trying a different 
pad, but not before my current ones wear out.  So...  If I do make the 
dubious decision of trying another pad, I'll get back to everyone on the

results.  At this rate of pad wear, I'm estimating about five to seven 
years on that.  Seriously.

-Cheers!
Mike

jpb3 wrote:
> Hi Randy, hope you had a good rally and better luck with your tandem
> than with the S!  I am going to copy the S car list with our train of
> correspondence. (If any lister wants to read through from the bottom
> up any feedback or advice is greatly appreciated!)
>
> This problem we are both dealing with seems to have gotten somewhat
> worse for me over the holiday.  I was running the OEM Avus 16" wheels
> which have very small clearance with the caliper so I was hoping that
> perhaps some sort of resonancy was happening between that rim and the
> caliper when the caliper warmed and expanded a slight bit.  Note I
> have been using "hoping" far too much in our conversations!  I put my
> 17" Bolero's on this weekend with mucho clearance but as you know it
> makes no difference!  As I have said before if it was not for the
> direct correlation with the brake pedal and the noise I would believe
> that the wheel bearing is bad, but seeing how that if you just barely
> tap the brake pedal the noise goes away momentarily (until you let
> off) I cannot bring myself to that conclusion, yet.
>
> So that we are on the same page I will list what is on my car and when
> the noise started happening.  I made a close visual inspection of
> everything when I did the wheel swap this weekend and nothing looks
> out of place, nothing looks like it should be making this noise!
>
> 95 S6, 928GTS calipers from Benson Porsche, brand new.
> OEM RS2 caliper brackets from VAG Parts UK, not machined.
> A8 (323mm?) Brembo rotors, brand new from PartsQuick.
> Ferodo DS2500 pads, brand new.
> Paragon braided hoses, banjo fitting.
> Porsche OEM caliper bolts.
> *034 bracket bolts* (note, these are standard metric head Vs. the OEM
> Hex head bracket bolts I have seen elsewhere)
> Super Blue, pressure bled.
>
> My braking system did not make any noise (other than pad squeal) for
> the first hundred or so miles.  I bedded everything in properly
> according to Mov-it instructions on their website.  As I have stated
> before my brakes immediately started making this groaning noise after
> a very hard stop to avoid a collision with someone who pulled out in
> front of me.  At the time I thought I may have bended something
> (bracket?) when I did that stop though that doesn't make sense.  I
> drove another 10 miles and pulled over and inspected b/c I thought
> that I was rubbing the caliper against the wheel or something of that
> nature.  Nothing looked amiss.  Noise then became intermittent and not
> too bad, only occasionally making itself known.  Turning left induced
> the noise, turning right quieted it or if I tapped my brakes it would
> stop for awhile.  It was only doing this for about two weeks before I
> was hit and my car than sat at a body shop for 5 weeks............that
> about brings us up to present.
>
> On the way home from body shop the noise returned, only this time
> worse. (More grinding sound, vibrations in the steering wheel.)  Put
> my 17" Bolero's on and now the noise is present every time I drive.
> It use to take some driving time (10-15 minutes) before the noise
> would appear, this has been reduced dramatically to about 3-5 minutes
> as evidenced on the way to work this morning.  It is now very loud and
> once it starts the only thing that makes it stop is turning right or
> tapping the brakes, and only momentarily when performing one of these
> actions.  Suspension deflection also seems to have an impact.  I live
> in very rolling terrain, with lots of hills and dips.  When the
> suspension loads up the noise is there, when it unloads (cresting a
> hill) it subsides somewhat for a second.
>
> ALL of the above sounds like a wheel bearing to me. HOWEVER, there is
> no play whatsoever when I have the wheel off the ground and do the
> Up/down, forward/back check for play.  Also, why would even the
> slightest (resting foot) on the brake pedal have any impact on the
> noise if it was a wheel bearing?  I can quiet the noise completely if
> I ride the pedal.
>
> I am at a loss and await to hear if your swapping of the rotors and
> brackets makes any difference.  If it does I am going to order new
> slotted rotors from Apikol but I just can't see the rotors being the
> issue. I re-read your original email and the theory of brake fluid
> expansion leading to pad dragging is interesting but my fluid is fresh
> and blue, no old left in the system and pressure bled.  Noise is
> getting progressively worse which again points to a wheel bearing.
> But is doesn't feel like a wheel bearing, it definitely feels like
> something is going on with the braking system on the passenger side.
>