[200q20v] Warped UFO's - not anymore!
QSHIPQ at aol.com
QSHIPQ at aol.com
Wed Jan 31 09:00:50 EST 2001
In a message dated 1/30/01 12:45:45 PM Central Standard Time,
b.m.benz at prodigy.net writes:
> Yeah, Bentley is hyper over changing the inner control arm bushings to
> correct brake shimmy problems, saying every 50K or to correct most any
> problem. IMO, this is a smoke screen to hide the fact that they couldn't
> figure out the source of the problem. In my vast experience, with 3 type
> chassis cars, I have never seen a bad inner control arm bushing.
I could send you quite a few that have the inner sleave separted from the
outer bushing Bernie, one on a car with new C/A with less than 10k on them.
Wider tires alone will rip the inner control arm, so will out of spec
bearings or outer ball joints. Once it's ripped, the hole for the inter
control arm bolt will elongate, which most wrenches miss, replacing just the
bushing and finding the same problem. Bernie, those inner bushings rip quite
often, many times due to the outer ball joint having play in it as well.
> for-hire wrenches have a broader perspective on this. In searching for the
> cause of excessive neg. camber in these cars, and prior to designing the
> 'Benz Brace' strut brace, I went so far as to push out a high mileage but
> apparently good inner bushing and reinstall it flopped and rotated 180
> degrees, proving that bushing creep set did not exist, as this had no
> on camber setting.
IME, excessive neg camber is due to 2 things: bad subframe bushings (causing
bad subframe alignment - this happens when you see a positive camber on one
side, way neg on the other - all 44 chassis cars). secondly, the upper strut
housing support is angled in towards the center of the car, over time those
housings push in further, since there is no brace to prevent it from doing
so. The way to ck this is to triangularly measure the engine bay. The fix
is to push the strut housing back out with either a jack setup or an
alignment machine. V8's are infamous for this problem.
> But the roll bar to control arm bushings see large angular missalignment
> changes which do fatigue and brake down the rubber, thus need to be
> inspected and replaced A/R and as you have done. This bushing primarily
> affects castor adjustment, so is not hyper-critical, IMO.
NO, this *IS* hyper-critical. Remember the ARB is also the triangulated
front mount to the control arm. That means, you have toe, camber and caster
problems, since the slop in the C/A>SB bushing is 360 degrees. The subframe
to ARB bushing slop allows fore aft movemet of the right vs left side of the
car during turning and braking. Bernie, I've done thousands of dollars worth
of front end work for 44 chassis owners (suspenion, racks the works), it's
not until you put in the new SB bushings is the wow! from the customer
shared. BTDT too many times.
FYI, the outer C/A to SB bushing is available aftermarket, but make sure you
get the german one (it has the PN on it), not the chinese one (usually
painted black, no numbers), they fail within a year. Same on the upper strut
bearings on the 5k application, there is no aftermarket for the v8/S4 type
(the one with the 17mm nuts) as of yet.
QSHIPQ Performance Tuning
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