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-   -   Help me diagnose my shimmy and shake! (http://legacygt.com/forums/showthread.php?t=186809)

EvilCamaroSS 06-01-2012 06:33 PM

Help me diagnose my shimmy and shake!
 
Background:

I balanced the tires recently.
I had the car aligned recently.
I replaced the pads and rotors last month (centric premium + stoptech pads)
I got an oil change and tire rotation 1200 miles ago.
I have KYB struts and shocks.
I did the 60K tune up around 20K ago. (plugs, coolant, etc)

Problem #1. No matter what I do, the ride in my car sucks. I can feel everything in the road, and while that doesn't bother me too much, the problem is a slight shimmy or shake when driving, it isn't much. You can feel it slightly in the wheel, and it seems to be worse the faster I go, around 70mph it is noticeable but the car really does not feel unstable. This has been happening for a while, maybe it is due to me paying more attention but it seems more noticeable now that I'm being bothered by the other problems below.

Problem #2 My steering wheel shakes when I am breaking in a normal fashion. If I hit the brakes hard, it does not shake, and if I hit them softly it does not shake, it seems like it only happens under normal breaking. This started happening Monday or Tuesday.

Problem #3 When I'm stopped at a stoplight my car shimmys. It shakes the whole car. it's not a violent shake, but it is noticeable enough for me to pick up on it no matter what is going on, even if I'm in a full blown conversation I can feel it. It does not appear that the idle is changing in any significant way during this. Kinda got me stumped here.

So what it comes down to, are what are the scenarios that could cause these issues? I know warped rotors could cause #2, but I seriously doubt they are warped, they have less than 3,000 miles on them. What else could cause this? Any parts in the front end? Any help is appreciated! Thanks!

SneakyFast 06-01-2012 07:21 PM

I'm guessing you got a shitty balance job and you need to bed in those new brakes.

legacy360 06-01-2012 07:23 PM

How are your front LCA bushings?

compsurge 06-01-2012 07:25 PM

Bent wheels. At least that's what they told me.

Others have reported (very rare) this being caused by the hub &wheel bearing assembly (they are ~$140 each). Only way to determine this is drive car on lift or jack stands without wheels on.

I am in process of replacing everything short of brake rotors. I have all bushings replaced and will be putting in new ball joints this weekend if my 3' bar works.

Also consider a road force balance, as Subaru recommended that for the shimmy issues.

As for your shaking, are you a 5MT? My flywheel was busted (dual mass springs) and vibrated the car like mad for the 20k I drove it like that before I realized it was the culprit.

EvilCamaroSS 06-01-2012 08:41 PM

Quote:

Originally Posted by legacy360 (Post 3920250)
How are your front LCA bushings?

Haven't had the car up on a lift yet or jacked it up. Could that cause any of those issues?

EvilCamaroSS 06-01-2012 08:42 PM

Quote:

Originally Posted by compsurge (Post 3920254)
Bent wheels. At least that's what they told me.

Others have reported (very rare) this being caused by the hub &wheel bearing assembly (they are ~$140 each). Only way to determine this is drive car on lift or jack stands without wheels on.

I am in process of replacing everything short of brake rotors. I have all bushings replaced and will be putting in new ball joints this weekend if my 3' bar works.

Also consider a road force balance, as Subaru recommended that for the shimmy issues.

As for your shaking, are you a 5MT? My flywheel was busted (dual mass springs) and vibrated the car like mad for the 20k I drove it like that before I realized it was the culprit.

I am 5MT... Were there any other symptoms with your broken flywheel?

compsurge 06-01-2012 09:15 PM

It vibrated a lot around 1500 rpm. That was about it.

EvilCamaroSS 06-02-2012 05:47 AM

Quote:

Originally Posted by SneakyFast (Post 3920249)
I'm guessing you got a shitty balance job and you need to bed in those new brakes.

Last night I bed the brakes. I'll take it out today and see how it is.

BigBad 06-02-2012 05:55 AM

Another possibility if you have ruled out what others have already mentioned is to check both front calipers to see if either set of pistons are sticking or partially frozen. This happened to me and it caused a shimmy/shake in the steering wheel when driving. Also noted when braking. I wound up replacing the offending calipers and the problem is gone.

terrible001 06-02-2012 12:28 PM

I definetly 2nd getting your tires road force balanced, this will tell you if there are any bends in the rim or if the tires have a shifted belt or something of the sort.
As far as the brake shimmy how are the caliper pistons? do they retract freely?
Even though those rotors are new they could possibly be warped to improper storage, like being stacked to the ceiling.
So have you had anyone else drive your car, esp someone that has a known brake or tire shimmy or driven their cars, maybe you are just to paticular

EvilCamaroSS 06-04-2012 04:39 AM

I'll look into the road force balance, however even after bedding in the brakes the shaking is still there. I don't think the rotors are warped because it's not consistent.

EvilCamaroSS 06-04-2012 11:06 AM

I made an appointment for the road force balancing tomorrow. They also saidthye owuld take a look at the front end, I'll post up tomorrow how it goes.

scoobyscoodle 06-04-2012 06:31 PM

My bet it either bent wheel, alignment, or uneven brake pad deposits on the rotors, remember, rotors do not "warp", they get uneven deposits on them and will cause a pretty substantial vibration as soon as you touch the brake pedal, and it will usually happen at freeway speeds under moderate braking.

Try to rotate your tires front/back. If either of your wheels is bent in the front this should make it obvious, because you really don't feel a bent rear wheel too much, and it can help to isolate the issue.

EvilCamaroSS 06-05-2012 03:41 PM

Had my roadforce balance today, The car drives much better, however the brakes still shake, the subaru dealer did not experience the shaking when pressing the brakes. There is still a slight vibration while driving, the technician said it was due to "choppy" tread on the inside of my tires, likely due to my driving habits or I may need an alignment.. I'm going with driving habits since my car runs straight as an arrow... Is there a way to avoid this? (Other than changing the way I drive)

They said everything on my car looked good, there was substantial even tread-ware on the tires, the rims were not bent, and all of the front suspension looked great.

Now, Solutions?

I was thinking about re-bedding in my brakes, I did the 3 stops from 50, 3 stops from 40, then cool procedure, is there a better way to attempt this?

Regarding the choppy tread, the only thing I can think of that could effect this is tire pressure, any recommendations?

compsurge 06-05-2012 05:27 PM

Choppy tread could be from alignment issues as well. The dealer I took it to gave me a similar prognosis + bent wheels. I know my alignment is definitely off since I did suspension and bushings (ball joints this weekend and an alignment next week, then new wheels + tires).

The slight vibration is most likely due to the tires.


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