[s-cars] Help diagnosing suspension issue

[Fred Munro]

Graham;

Bad control arm bushings usually cause this problem. Wheel bearings get
noisy but usually don't cause massive vibration until they've spit out all
the balls. Replace both control arm bushings and the sway bar bushings. If
there is any play at all in the ball joints, you might as well replace the
entire control arm. If you go with aftermarket control arms, get the TRW
arms - the Mahle ones don't last.

HTH

Fred Munro
'94 S4
'97 S6


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of Graham Hicks
Sent: May 24, 2006 12:02 AM
To: S-Cars list
Subject: [s-cars] Help diagnosing suspension issue


I've got a '97 S6 and need some advice on what to look for.
Coming home from work there is a great sweeping left that is slightly down
hill and great for running up speeds.  I regularly run 140kph in that
stretch, (90mph) but the other night there was a bad vibration.  Bad enough
it made me think my front right wheel had come loose!
    I pulled off and the wheel was tight and the tie rod was tight so I
continued home and started jacking up each corner to see if there was
something loose.
Tie rod ends are good, no movement up down or lateral from any corner, and a
2 foot pry bar revealled no play in the suspension when jacked up.  Based on
my visual inspection the left rear lower, inner control arm bushing looks
like it needs to be replaced but still seems solid. The reason I say that is
because it looks like the metal sleeve has separated from the rubber part
(at least partially).
    I have repeated the corner at various speeds and above roughly 120kph
and under acceleration the vibration or feeling that the right front is
wobbling has been duplicated so there has got to be something wrong.  I
swear its in the front passenger but would the the rear control arm give me
a wobble feel if when weighted there is actually play in the bushing? (note
that the steering wheel translates the vibration and that if I straighten
out and lift off the throttle - it stops)
    Also, IF the front passenger wheel bearing were gone, would there not be
a noise or movement to tell me there was a problem? Does anyone have
experience with the control arm bushings to tell me what kind of bill I am
looking at to have them replaced?  I believe I could remove the control
arms, but I do not have a press and would have to have it re-aligned
afterwards right?

Graham Hicks
  UrS6Turbo at Yahoo.ca


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