Chasing a front end shimmy

[Max Capacity]

Both LCA's were replaced in Nov 2019 after the shimmy was noticed.

[SubOperator]

Both LCA's were replaced in Nov 2019 after the shimmy was noticed.

 

 

Hmm, IDUNNO then. Need to think what da heck is going on. The fact that both our cars are experiencing likely same problem, and some others are also in this thread makes me believe there is something age/wear related. But you have gone so far replacing parts that I would as well, and still got no resolution.

[shralp]

Ditto here guys, virtually the whole front suspension has been replaced including the pass caliper, in the last 36 months. Was hoping swapping in a new OEM GT caliper would fix the issue since my pass side rebuilt one locked up. But no, it’s still there... I mean it’s not bad but definitely annoying, especially since it’s an intermittent problem.

[SubOperator]

Here I am just thinking aloud, not trying to get Max to change this part. So my axles are still original. I rebooted both but they are 15 years and 232K miles old. Can there be some wear inside the cartridge that makes the rollers catch on some uneven surface inside the cartridge, or force rollers in some bad angles? Just thinking as to what happen when one feathers the brakes, there's got to be some load on those axles that's opposite in direction to acceleration.

[SubOperator]

In my case I did the 6MT swap recently and the shimmy is still there so at least in my case it is not the tranny.

[Max Capacity]

Both front axles have been replaced, left in Nov. right in March.

 

The right front hub is the only thing other then the Koni's that have been on there for many years. It is a OEM hub, replaced in 2013 I think. Shop's say the hub is tight.

[shralp]

Yup, new OEM axles and hubs here as well

[boxkita]

post up alignment sheets?

[08SpecB_DE]

post up alignment sheets?

 

I log in everyday hoping to see one

[shralp]

Spec sheet from the local Subaru dealership that I'll go to from time to time if I'm not using Cobb Surgeline. This was part of a left front axle, Right front knuckle replacement. Car has GT front calipers, R is refurb'd, L has OEM new replacement, new front axles, new knuckles, newer Whiteline sway with newer moog endlinks, DBA 4000 rotors showing no signs of uneven wear. Pads look good. New'ish ball joints, and replaced all the control Arm bushings last year with new OEM ones. Parts listed above have been installed in the last 36 months.

[boxkita]

interesting. toe & thrust angle are not zero. The right side has more of everything than the left. Getting toe to zero is usually easy unless something is out of whack in the system.

 

My mini truck has a bad spindle. Replacing it is a suck job, especially after I discovered it was bad after replacing everything. It would hold sn alignment for about 50miles than go out, badly. The shimmy was pretty bad, to the point of damaging the tires.

 

ehat was the rationale for replacing the spindle?

[shralp]

The CV blew up on the left front axle and needed to be replaced. Wheel bearing went bad on the right front. I purchased the car from a forum member out of Ohio. You can imagine how the wheel bearing felt about being separated from the knuckle. Wasn't havin' it... Based on factory spec everything seems to fall well within that so thats why I'm stumped. Edited May 15, 2020 by shralp

[08SpecB_DE]

"In the green" isn't always good enough. Your front toe for instance, both front tires are driving down the road like this " \ \" or even closer "l \" Same is true for rear camber. I bet you'd feel a big difference just fixing the front toe but .7° difference in rear camber is enough to where I'd recommend addressing it as well.

[boxkita]

^^^ this.

just cause it's green doesn't make it right.

[08SpecB_DE]

I'd take it back and demand they fix at least the front toe since there's no factory rear camber adjustment. Your tires are essentially fighting the road so any bump or dip in the road will exacerbate that. Then, you can work on getting the rear camber straightened out. Until then, keep the tires rotated often to reduce the wear on the inside of the tire.

[shralp]

Probably just take it to Cobb Surgeline for alignment, I throw up in my mouth a little bit every time I walk into the dealership...

[08SpecB_DE]

I just noticed the alignment sheet is from 2019 I thought you recently had it done. I'm sure if you tell them you want the specs as close to the actual specification as possible, not just within tolerance, they will take care of you. That should be the mindset of anyone performing an alignment but most techs will not take the time unless it's on their own vehicle.

 

Edit: Now would be a good time to fix the rear camber since the alignment is not going to be free. I could be wrong, but I think the Whiteline bushings give you up to .7° of adjustment.

Edited May 16, 2020 by 08SpecB_DE

[shralp]

Jeez guys last October is not that long ago . Had shimmy before taking it in, had it after... The thing is this is an intermittent issue which I still find strange. I’ll most likely take it to Cobb Surgeline for the next alignment and request they get the specs dead tits BUT if the alignment comes back proper I’m gonna bet all of you the shimmy is still there. Def not spending any cash for Whiteline bits on this car, I don’t feel that it’s too much to expect this car to be right without throwing all manner of aftermarket suspension parts on it. I’ll go wild on the track car but this is just my daily and I’d rather not modify further than it already is. Edited May 16, 2020 by shralp

[08SpecB_DE]

Fair enough. Have you tried checking the rotors with a temperature gun after you experience the shimmy? When the shimmy is present, does it do it all the time, only when accelerating or only when braking?

[Enlight]

That would isolate whether it's a brake or suspension issue.

[SubOperator]

Jeez guys last October is not that long ago . Had shimmy before taking it in, had it after... The thing is this is an intermittent issue which I still find strange. I’ll most likely take it to Cobb Surgeline for the next alignment and request they get the specs dead tits BUT if the alignment comes back proper I’m gonna bet all of you the shimmy is still there. Def not spending any cash for Whiteline bits on this car, I don’t feel that it’s too much to expect this car to be right without throwing all manner of aftermarket suspension parts on it. I’ll go wild on the track car but this is just my daily and I’d rather not modify further than it already is.

 

 

That and another thing is that I don't see how misalignment causes it to be intermittent. Yesterday got the car out of garage for the first time and it drove fine for first 10 minutes, then just tapping the breaks to kill some speed, crazy shimmy with steering wheel bouncing, then uneventfull ride to several stores and back home.

 

 

Car does not pull to any side nor does it exhibit any incorrect tire wear patterns. Another details - when shimmy happens, car still drives straight , I tried that several times it happened.

 

 

I just read at another car forum that a guy used a chinese knock-off gopro camera to attach it to his truck's subframe to figure out successfully what was at play. May be that's something to try.

[SubOperator]

Fair enough. Have you tried checking the rotors with a temperature gun after you experience the shimmy? When the shimmy is present, does it do it all the time, only when accelerating or only when braking?

 

That would isolate whether it's a brake or suspension issue.

 

 

That's only if the caliper is sticking. My theory (one of) is that the a caliper is actually not getting enough pressure to properly bite, thus causing difference between braking force on either side, and thus shimmy. Then you press on the pedal it eventually bites as it should and shimmy goes away.

 

 

 

As another proof towards that theory is that if I step on brakes HARD couple of times, the shimmy seems to go away for some time.

 

 

 

Stepping hard on brakes may make other things move in suspension of course. But I've changed them all pretty much except for rack.

[outahere]

For the past 7 months or so I have been chasing little issues from wrapped rotors to a intermittent shimmy at 68-73+mph. Started shortly after I put Brembo pads on all four and new front rotors and rear rotors (AM Auto Parts) last Sept 14th .

 

sometime shortly after I began to feel the "wrapped rotor" shimmy under braking.....

 

Have you ever measured the axial runout on the rotors? Even with new rotors you can't always assume it is OK.

[Max Capacity]

Have you ever measured the axial runout on the rotors? Even with new rotors you can't always assume it is OK.

 

The car has had numbers sets of rotors in the 16 years I've owned it. But yes, when I picked up the NAPA rotors from being turned, I was told those had quite a bit of run out.

 

I have the rotors that were on it last Summer and they were turned by the same shop and nothing seemed out on them.

 

On the drive home today the first 20 miles at 70mph was fine. As I got about 10 miles from home still on CC at 70mph on East Bound rt84 I began to feel a slight shimmy for a couple miles, it stopped after that.

 

This was the same area on rt84 that I noticed the shimmy after picking the car from having the rubber flex lines and two hard pipes on the rear changed last week. But it that time, it was much more noticable, today was very slight.

 

Over the weekend I put new rear rotors Advance Auto Parts and Carquest Ceramic pads on the car. Went out and bedded the brakes in. Did 5 or 6 almost stops from 60mph. I could see clouds of brake dust in the rear view mirror and smell the brakes, continued to drive another couple miles without touching the brakes.

 

 

My drive to work is at much lower speeds, normally I don't go over 65mph, most of the trip is at 60mph on CC. No hurry to get to work. LOL

 

Oh, the old rear Brembo pads had to be hammered out of the caliper bracket. There was grease on the tabs when I installed them. The four pads had different amounts of pad worn away.

 

The new Car Quest Pads from Advance Auto Parts move easily in all four calipers.

Edited May 18, 2020 by Max Capacity

[lotadisa]

Try checking the castle nuts on your tie rod and control arms. I had a bad intermittent shimmy when I forgot to replace the cotter pin. The fact that your issue goes away when fiddling with the brakes tells me that the castle nuts likely are not the issue, but its worth eliminating the possibility.

 

Another observation, took the 86 Ford F150 for a ride today, it only has 139,000 miles on the chassis and 43,000 miles on the Ford crate motor installed in Sept 1991. While I'm driving it around the local streets, Tutuapp 9Apps ShowBoxI think to myself, wish the wagon drove this nice... LOL

Edited May 19, 2020 by lotadisa