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Old 06-21-2011, 07:06 AM   #17
JoeFromPA
Registered User
 
Join Date: Jul 2010
Location: West Chester, PA
Posts: 211
Yikes - looks like this is going to be my winter 2011 job. 2010 was spent tuning the car up, replacing all the fluids, and replacing the motor mount.

Now I've got a rattling heat shield (easy), squeaky rear brakes (easy), a horn that stopped working (we'll see how easy), and the front end shimmy (ugh).

I'm almost certain this is bushing related at this time. I took the car up to ~105mph yesterday on an extremely clear, flat section of (track) roadway in great road surface condition. The car actually felt great from 85-105 and had more shimmy at 70-80mph. It's not distinctly rotational in nature, though it tends to be harshest when it kicks in at the higher speeds. Bushing-related shimmy makes more sense considering sometimes there's no shimmy at a speed and other times it's more severe.

Further, I believe the reason the shimmy changed in nature when I switched from my winter to summer wheels/tires is because the winter rubber has different dimensions and absorbed more wiggle - whereas the michelin pilot sports are far stiffer and will twitch more by their stickiness.

I'm going to focus on the front end at this time since that is what will cause steering shimmy. I'm thinking I should tackle it like this:

1. Replace front track and control arm bushings (inner & outer)
2. Remove, inspect, and possibly replace outer tie rods
3. Remove, inspect, and possibly replace inner tie rods

Stop there and examine shimmy - if dramatically different, get the car re-aligned and call it a day.

If it called for replacing both tie rods, and I did all the work myself except I took the control arms to my mechanic to get the new bushings pressed in, I'd expect this all to come in under $500. Tie rods are around $100 for both inner and outer on pelican parts. The bushings are about $170 from powerflex (which is also sold at pelican parts as the only full rubber replacement bushing.

So that's $270 - figure $50 for pressing the bushings in, $100 for the alignment, and $80 for miscellaneous tools (like a tie rod end puller) and random parts.

Yep, $500 for a freshened up front suspension and steering. Yikes.

Might also be worthwhile to drop another $100 at that point and have the tires rotated laterally and re-balanced. One more area to get rid of shimmy, and might be worth $100 to extend the tire life that much....
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