[200q20v] Warped UFO's - not anymore!

[QSHIPQ at aol.com]

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 
brake
>  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 
44
>  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.

>Maybe our
>  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 
effect
>  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.  

HTH

Scott Justusson
QSHIPQ Performance Tuning
Chicago