UrQ steering shaking at speed: me too.

[rob hod]

    I have had similar problems but on my 100 FWD. A steering shimmy at just
under 60 mph, and a very light one around 30-40mph. Any speed above 65 the
problem goes and is absolutely rock steady. All suspension gear is in very
good order, no slop anywhere.

    I think its safe to say that if you don't get a shimmy under braking you
can rule out rotors, but it could still be binding calipers due to old
piston seals or worn/binding guide pins. I've eliminated all these
possibilites.

   However there are three possibilities left in my case, 1, the tires are
newish and made the problem worse from new, I had them rebalanced and the
problem seemed to go then return. Maybe they've never yet been balanced
quite right or they;re a bad batch (goodyear NCT3)
    2, I know the inner front CV is worn, maybe it is somehow tansmitting
vibration to the steering gear.
    3, Maybe the front wheel bearings, but I can't detect much movement at
all either on the ground or on stands.

    One really crazy thing I noticed is that when recent new pads were
bedding in they would do a faint cheep-cheep noise with my foot off the
brake pedal, This disappeared when braking even lightly. Fair enough but the
funny thing was that at say 20 mph and a very light throttle (or more
throttle) the cheeping disappeared but would return with the gas off, i.e.
on the overrun. Makes me wonder if the wheel bearings are just that bit worn
to allow all these symptons, yet not worn enough to make any noise or a
rough ride etc. Just a thought.

    Incidentally my CGT displays none of these vices - rock steady at all
speeds, so I take that as my benchmark.

    All in all I've decided to live with it for the time being as its not a
major kick, and you can always drive through the vibration period. In the
past I once had a similar problem that turned out to be a broken tyre belt.

    Just a word about out of round tires, - I've run cars on stands before
now and noticed that they can appear to be quite badly out of round, yet
drive perfectly. So if you run the car on stands and the wheels look like
they're all over the place, don't assume that they're the cause of the
problem.



 YMMVas usual.


rob
----- Original Message -----
> Message: 1
> Reply-To: <larichard at compagnonderoute.ca>
> From: "Louis-Alain Richard" <larichard at compagnonderoute.ca>
> To: <audi90sq at yahoo.com>
> Cc: "urQuattro List" <urq at audifans.com>,
> "Quattro List" <quattro at audifans.com>
> Subject: UrQ steering shaking at speed: me too.
> Date: Tue, 5 Nov 2002 11:51:33 -0500
>
> I am in the same boat.
>
> Brake pedal does not pulsate at all. New front Boge struts, =93green=94
fro=
> nt strut mounts and front wheel bearings. Tie-rods and ball joint looks
OK,=
>  as well the A-arm bushings (very stiff). Discs were cleaned and the
mounti=
> ng surfaces + the hubs were sandblasted as well when I did the bearings.
P=
> ads are VW-Audi brand.
> Other parameters are:
> Summer tires: New Dunlop SP5000 on Ronal 6 inchers, light shimmy on
steerin=
> g at 60-70 mph, no shake at all on hard braking, steering shakes BADLY
when=
>  I just feathers the brake pedals.
> Winter tires: 1 year old Pirelli W240 on non-hubcentric steel wheels,
every=
>  parameter is worst with these wheels
>
> I will replace the guide pins tonight, just to be sure.  I will check
rotor=
>  balance, just to be sure.
>
> Q1: could it be the main drive-shaft, with a bad CV or U-joint ?  When
appl=
> ying brake, front tires compress, rolling diameter is less than rear,
torqu=
> e is induced in the DS and vibration occurs ?
> Q2: If it=92s the rotors, then why no vibrating brake pedal? Because our
ca=
> rs are hydraulically-assisted, and this device =93absorbs=94 more than a
va=
> ccum assist ?
>
> Other question, not related.
>
> Q3: I need a diagram of the wiring for a standard sealed-beam hi-low
headla=
> mp.  H4 is a different wiring pattern and since both filaments share the
sa=
> me ground, I ended cross-wiring lows and highs=85  Yeah, I know, this is
tr=
> ivial to everybody but I completed this job last night at 1:00=85
>
> Thanks in advance,
>
> Louis-Alain
> 83 urQ avec the correct DOT headlamps now, but blinding everybody :-))
>