[s-cars] Big Reds making Sandy red in the face...
steve powers
steve at thepowers.net
Sat Feb 21 19:35:03 EST 2004
I'll second what Mark says about truing. I've got the same setup
and went quite awhile without doing it. It only ever had a minute
wobble from new. The wobble got progressively worse over time. After
truing, it's gone. $40 well spent.
Steve Powers
> -----Original Message-----
> From: s-car-list-bounces+steve=thepowers.net at audifans.com
> [mailto:s-car-list-bounces+steve=thepowers.net at audifans.com]
> On Behalf Of Mark Strangways
> Sent: Wednesday, February 11, 2004 4:02 PM
> To: Sandy Sligh; s-car-list at audifans.com
> Subject: Re: [s-cars] Big Reds making Sandy red in the face...
>
>
> Also note, that truing is suggested once the rotors get a
> few good initial heat sets in them. I tried and tried to
> trace a problem I had with my 996tt over 993 set-up, it was
> a very similar situation. A bit of vibration at very high
> speeds, and some pulsing in the pedal when braking... I
> turned out to be a bent rim believe it or not.
>
> But I tried the indexing and had them turned prior to making
> the discovery that my rims where bent.
>
> Mark S
> ----- Original Message -----
> From: "Mark Strangways" <strangconst at rogers.com>
> To: "Sandy Sligh" <sdslig at yahoo.com>; <s-car-list at audifans.com>
> Sent: Wednesday, February 11, 2004 6:48 PM
> Subject: Re: [s-cars] Big Reds making Sandy red in the face...
>
>
> > The rotor is designed to float on the hat.
> > So, torque is a very important factor. So are the many
> small bolts and
> funny
> > looking nuts that allow you to reach torque but still
> allow the rotors
> > to float. I don't know if you used the new ones with the
> rotors you
> > bought, I assume you got your rotors complete with the
> Porsche hats
> > from the factory. I
> would
> > strongly suggest you don't re-use the old fasteners, use
> the new ones
> that
> > shipped with the rotors.
> > Second, you will need to index the rotors on the hat. Try
> placing the
> rotor
> > on the hat 180 degrees from what it is now.
> >
> > There is a factory porches sheet that is on the bira site
> that gives
> > the proper torque values and sequences.
> >
> > Mark S
> > ----- Original Message -----
> > From: "Sandy Sligh" <sdslig at yahoo.com>
> > To: <s-car-list at audifans.com>
> > Sent: Wednesday, February 11, 2004 6:20 PM
> > Subject: [s-cars] Big Reds making Sandy red in the face...
> >
> >
> > > Ok, this email will be part Sandy's-an-idiot and Sandy's-a-newb.
> > > Whichever is worse, who knows.
> > >
> > > SO. The S4 fails tech inspection due to worn-out front rotors
> > > (993tt). No problem, I'll go pick up a new set and put them on
> > > myself. How hard could it be really.
> > >
> > > I get the rotors in my hot little hands, pull off the
> > > old rotors which are cracked inside edge to outside
> > > (nice work, Bruce!! Thats some hard drivin!) Pop the
> > > rotor hats out and install said rotor hats onto brand
> > > new rotors. WHee!!! Going pretty good.
> > >
> > > A week or so later I develop two vibrations. One felt
> through the
> > > steering wheel (small amplitude) when cruising at 120kph
> and higher,
> > > the second(medium
> > > amplitude) when lightly braking from 100kph and down
> > > to about 40kph. This second one I feel much more in
> > > the steering wheel and also through the brake pedal.
> > > With the hands off the wheel and braking, the steering wheel
> > > noticably rocks back and forth rapidly, maybe 3/4" to 1" in each
> > > direction.
> > >
> > > "There is no WAY I've warped these rotors!", Sandy
> > > cries.
> > >
> > > I pull them off, pull out the hats and clean up the
> > > mating surfaces considerably, mostly scraping off what
> > > I assume was built up pad material. Reinstall the
> > > rotors.. same deal, vibrations are unchanged. (BTW,
> > > I've been very methodically about torquing my wheels
> correctly. In
> > > a star pattern, first to 45ft-lbs and then to 90. )
> > >
> > > Off they come again and I notice outlines of the brake
> > > pads imprinted on the new rotors.. AH HA! Stoptech's
> > > brake FAQ tells me what that is! I remove those rotors
> > > and reserve them for later scrubbing with garnet paper
> > > per Stoptech's suggestions (hopefully a new set is not
> > > in order. $$$$) In the meantime, I reinstall the old rotors and
> > > plan on babying them until I either am ready to try the new set
> > > again or break down and buy another set.
> > >
> > > Well, low and behold, the old rotors are displaying
> > > similar albeit slightly better symptoms.
> > >
> > > Questions:
> > >
> > > A) Do the sources of my vibrations reside elsewhere?
> > >
> > > B) Am I missing a crucial installation step, i.e. a
> specific torque
> > > pattern on the rotor hat bolts? (I devised a type of
> star pattern
> > > and just cranked them down till they all felt equally tight)
> > >
> > > C) Do I need to go back over the mating surfaces again
> > > and damn well make sure they are clean and flat?
> > >
> > > D) Maybe because I didnt' change the pads at the same
> > > time? (why would this affect running the old rotors..
> > > )
> > >
> > > E) Something else entirely?
> > >
> > > Please, anyone with BTDTs or suggestions unleash them
> > > upon me. I've spent more than a few nights in my
> > > parking garage pulling wheels, pulling calipers,
> > > pulling rotors, cleanings, tightening, reinstalling,
> > > wash, rinse, repeat. Help make me smarter and the ride
> > > out the the shop.
> > >
> > >
> > > Thanks in advance
> > >
> > >
> > > Sandy
> > >
> > > __________________________________
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> > > Yahoo! Finance: Get your refund fast by filing online.
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