Alignment

[Jay Kempf]

"I did have an interment small shimmy that would come and go at  60-75mph.  
Replace tie rod end and 80% went away, had the toe set and car  drives fine.

 Front end feels great when driving.  The only time I  have heard any 
squeaking is after I have jacked the car up to change oil.   It may squeak
for a 
few moments after the car is back on the ground.   Squeak goes away after 
drive a few blocks, I presume it was the suspension just  seating itself
after the car was lifted."

The whole point of this front end design is to be able to replace components
without affecting alignment and that alignment is pretty stable and not as
critical because the virtual axis negates a ton of the cosine problems of
suspension off the design neutral point. So fixing it is like fixing
anything on a modern car. Make sure the parts are all up to spec and then
measure. Shuffle the lower frame and it should come into spec. If it doesn't
two things can be wrong: something is bent or something isn't up to spec
even though it all looks that way. The problem with this design is the
rubber bushes don't show their wear like older designs do. The rubber can
become unbonded from the aluminum arms where they attach to the body. The
lower rears are the ones that take the beating from compression. You cannot
feel how shot they are by just prying unless they are gone. Your 60-75MPH
coming and going shimmy is a dead nuts symptom of one or both of your lower
rears being weak. There are some things that mechanics don't normally do
when dealing with these cars. One is they tighten the suspension when it is
sagging on the lift and the bushings don't like to be twisted in their
normal range and they wear out early because of it.

If you haven't changed out your lower arms and you have 100+k miles you
probably need to. If they didn't put the new style on (mid year factory part
under a recall) then you should look at the part numbers and find out. If
you want to inspect them properly, crack the lower rear ball joints and then
move the arm in the axis of the rubber bushing. If they are done they will
rotate freely instead of feeling the bushings resistance. If they move that
is the source of your squeak (non metallic sounding) and also the source of
your shimmy and your alignment problems. Lower rears are $100 a piece and an
hour of labor to do both. You may also have cheap chinese knock offs if you
don't have history on the car. Those are known to have the wrong durometer
and the wrong type of elastomeric bushings and they can go bad in a couple
thousand miles.



jfk