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Chasing a front end shimmy


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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. Rebedding the brakes helped some.

 

I also replaced the right front caliper again, it did have a sticky slide pin. That caliper had been on there for 18 month's, NAPA gave me a free replacement.

 

That helped some, In Nov, four new Blazzicks on the winter wheels and a few weeks later the shimmy like tire balance appeared.

 

Had my trusted mechanic check it out, they rebalanced all four, replaced the left front axle again and the hub with my spare Timken. He also put new NAPA Premium rotors on the front A week later I rotated the tires and drove it all winter, about 7000 miles. Seemed ok just kept it under 67mph most of the time. I just put up with the intermittent shimmy.

 

Three weeks ago, four new DWS's on the summer wheels. Still have the shimmy at highway speeds, sometimes.

 

Couple weeks back had a local garage rebalanced all four, found one rim has a hop in it on the balancer. Had them replace the OEM 290,000 right front axle as it had play in it when you grabbed it and moved it up/down.

 

Intermittent shimmy still there.

 

The other day I picked up another Free NAPA caliper. Put it on today. The old caliper seemed ok, the slide pins worked and the pistons slid back easy with the C clamp.

 

So, what could be the problem... I did notice the Brembo pads were tight in the spring clips. Not tight on the tabs, but tight on the sides/ends of the pads where they fit in the lower area on the spring clips. I ground them down a little.

Drove the car a few miles on the highway to bring the old caliper back to NAPA.

 

Seemed to help a lot.

 

Came back home, pulled the left front pads and ground them down too. The 30 mile drive to work tomorrow will tell. Could the fat/sticky pads have caused this ? I do use the green brake grease on the tabs.

 

 

Also dropping the car off at the trusted mechanic after work tomorrow to have them replace the steering rack and both motor mounts.

 

I also R+R'd the tranny and rear diff fluid today. For as noisy as the tranny is the fluid came out pretty clean, very little metal on either drain plug, tranny or rear diff.

 

I'll have the wheel with the hop fixed later in the week. There's a place called The Wheel Shop about a mile from work, had them fix other wheels in the past.

 

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, I think to myself, wish the wagon drove this nice... LOL

Granted the truck has gotten a lot of love over the years, more money than any sane person would spend on it. It was my dad's...so it's hard to let it go.

 

EDIT, so its easy to find a right steering rack in the future, got this from post #51 here,

https://www.mavalgear.com/maval/catalog-search

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Subbed for an answer. Same thing here also intermittent in that speed window. It’s independent of tires, rims as both my summer and winter set ups have the same issue. New OEM front right caliper fixed most of it as the piston was seized. Plenty of meat left on my Carbotech ceramics and running nice DBA 4000 rotors :( Edited by shralp
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I'll try and remember to post a update from work tomorrow.

 

My big clue happened last Saturday on the drive to VT and back in one day. I had washed the car on Good Friday and sprayed tire shine on the tires. When I got back VT I noticed the right front had lot more brake dust.

 

I have had to grind down the tabs on other brake pads in the past, so its not like I shouldn't have had a clue...

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Wheel Bearings?

 

I also had a front strut loosen up the top nut on the Top Hat / Top Mount... Would think you would notice that - it clunks/clicks over bumps more so than a shimmy - but worth a look.

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As I said they put a new left hub on back in Nov. I did check today and the right is tight.

 

Both mechanics said everything on the front end is tight, the local guy even said, you tell the car is taken care of.

 

Just took the car for two 5 mile runs on the highway with CC set at 70, no shimmy.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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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.

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Bessie II's Thread

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Those will be checked when they replace the steering rack this week.

 

I'll add the car was aligned a few weeks back also. All was tight then.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Make sure to request that they look into it specifically. Mine developed right after an alignment - but I didn't ask them to look everything over. I figured they would tell me if they saw anything out of place but I was wrong. It might be worth re-tightening those nuts and putting in new pins unless it was done already recently.

 

Not gonna lie, I'm also enjoying the fact one of our resident gurus is turning back to the forum for advice.

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Bessie II's Thread

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Max, I've been fighting intermittent shimmy under highway braking and driving for years now. As you said, at some point I just put up with it since I got tired of taking it to mechanics and throwing parts and time at it.

 

 

What I know this far:

- tires/wheels do not matter, I have 3 different set of rims and had changed tires of them, always balancing to "high-speed" balance;

- issue is intermittent, some times I can drive for few months without it, sometimes I can have real bad day/week;

- weather/season does not seem to matter.

 

 

It's been few years now and I replaced many parts in front suspension. Easier to say what's original:

 

 

- steering rack;

- shocks (Bilstein HDs from years ago);

- brake hoses;

- brake master cylinder;

- ABS controller.

 

 

Everything else was replaced, some things such as balljoints and brake rotors/pads more than once.

2005 LGT Wagon Limited 6 MT RBP Stage 2 - 248K

2007 B9 Tribeca Limited DGM - 258K

SOLD - 2005 OB Limited 5 MT Silver - 245K

SOLD - 2010 OB 6 MT Silver - 205K

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Well the one thing neither of you have mentioned here, control arm bushings. If one arm has a more worn bushing on one side than the other and you hit a bump it can throw the alignment off just a touch that you can only feel at higher speeds. If you get the car off of the ground and give the lower control arms a "pull" with a long pry bar see if there is any difference between each side.

 

I had this a few years ago on my 05 Legacy GT, I swapped out the main bushings for Energy suspension poly bushings and it tightened up the front end perfectly. Of course you will need an alignment after!

 

I'd also do a good check on steering rack play and inner and outer tie rods too.

08 Spec B, insta: @08_spec_b, 10 SH Forester insta: @shfozzy
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Oh, sorry both LCA were replaced in Nov too. Thanks for reminding me. I should have had my little note book which has all the work done to the car when I started this thread.

 

This is the second set of those on the car.

 

The steering rack is pretty wet with PS fluid from the leaks.

 

I'm guessing the tight brake pads is the cause of the shimmy. Heading off to work in a few minutes, 30 miles on the highway, that should tell...

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Update, the now very slight shimmy is there at times. Drop down to 65mph, it stops.

 

Just called the trusted mechanic, he'll order a steering rack today.

 

Thinking about having my spare set of front brake rotors turned and install them later this week. There is still the slight shimmy when stepping on the brake pedal to come to a stop. May try the re-bedding process.

 

Funny after rotating the right front Brembo brakes pads a couple weeks back, there is now a 1/2" raised band on the outer edge of the inside surface of the right front rotor.

 

The shimmy now is much less then it was before so I think I'm moving in the right direction.

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Steering rack is original on mine but it does not leak nor can I feel any play in it. I did check with wheels on the ground playing with steering wheel and then with the wheels off the ground trying the wheels themselves, no play. Tie-rods were replaced too. Plus I would think steering be present most of the time.

 

 

I did replace the LCA bushings too, running second set of STI bushings. WL offset before that.

 

 

 

After rebuilding front calipers it did help for 2-3 months but then the issue came back. I have since replaced all 4 calipers with brand new OEM calipers, not even rebuilt - brand new. Same - it helped for some time but the issue is back with me. New rotors too at that point (Centrics Cryo) with Akebono pads.

 

 

I am suspecting either brake hoses swollen to a point where they prevent proper flow. Or ABS controller messing up sometimes. Heavy braking cures the issue for sometime but after trying different rotors/pads combos I tend to think the issue is elsewhere.

2005 LGT Wagon Limited 6 MT RBP Stage 2 - 248K

2007 B9 Tribeca Limited DGM - 258K

SOLD - 2005 OB Limited 5 MT Silver - 245K

SOLD - 2010 OB 6 MT Silver - 205K

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No, my brakes flex lines are what came on the car.

 

I'll say on the 5 mile drive from work to the highway exit ramp there was no shimmy at 70mph. The car is at the trusted mechanics. I was able to find a long stretch on the backroads to rebed the brakes and let them cool well.

 

Others with this issue, please see how tight your brake pads are in the spring clips.

 

After I ground mine down, they were easy to load into the caliper bracket, but would tend to fall out of the bracket if I wasn't careful positioning the bracket back on the knuckle. I took off a couple thousands not a big amount. I did coat them with the green brake grease.

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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Update, the now very slight shimmy is there at times. Drop down to 65mph, it stops.

 

Just called the trusted mechanic, he'll order a steering rack today.

 

Thinking about having my spare set of front brake rotors turned and install them later this week. There is still the slight shimmy when stepping on the brake pedal to come to a stop. May try the re-bedding process.

 

Funny after rotating the right front Brembo brakes pads a couple weeks back, there is now a 1/2" raised band on the outer edge of the inside surface of the right front rotor.

 

The shimmy now is much less then it was before so I think I'm moving in the right direction.

 

When you say raised band, do you mean similar to a lip on the edge of the rotor like one would see on a really worn down rotor? Were the pads worn unevenly? Intermittent shimmy, excessive brake dust and the raised edge on the rotor definitely sounds like that was your issue. The brake pads should be very easy to remove from the brackets. I've had issues with rust buildup under the hardware causing the pads to be tight.

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In my case, what's interesting is that heavy breaking makes the issue disappear for some time.

 

 

 

Now I can speculate what exactly heavy breaking causes to happen in the brake system/suspension/wheels.

2005 LGT Wagon Limited 6 MT RBP Stage 2 - 248K

2007 B9 Tribeca Limited DGM - 258K

SOLD - 2005 OB Limited 5 MT Silver - 245K

SOLD - 2010 OB 6 MT Silver - 205K

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i always like the simple things first, have you checked your alignment? Thats around the speed where you can feel wheels trying to go different directions. Does the car drift at the speed when you let go of the wheel?
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I had to re read thread just to make sure... all this suspension work and changing of parts and no mention of alignment. Imo these cars really need a good alignment to drive right. If you haven't checked the alignment I would do that first, especially because its only happening at that speed.
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When you say raised band, do you mean similar to a lip on the edge of the rotor like one would see on a really worn down rotor? Were the pads worn unevenly? Intermittent shimmy, excessive brake dust and the raised edge on the rotor definitely sounds like that was your issue. The brake pads should be very easy to remove from the brackets. I've had issues with rust buildup under the hardware causing the pads to be tight.

 

The raised portion is on the rotor surface where the pad contacts it. when I rotated those two pads a couple weeks back that was not there. It is about a 1/2" wide. The old inner pad, now the outside pad looks normal. The new inner pad, which was the old outside has the 1/2" recessed grove to match. That area also show dust build up.

 

The rotors are NAPA Premium rotors.

The pads are Brembo's.

 

The Spec B has the same NAPA rotors, I can't remember which Pads but had four NAPA calipers. All is fine with that car.

 

I'll also add when I pulled the pads a couple weeks back I wire brushed off stuff, build-up on the leading edge of the pads and just hit the surface quickly with the wire brush.

Edited by Max Capacity

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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I had to re read thread just to make sure... all this suspension work and changing of parts and no mention of alignment. Imo these cars really need a good alignment to drive right. If you haven't checked the alignment I would do that first, especially because its only happening at that speed.

 

 

Thanks Enlight.

 

It was also aligned when the ball joint was replaced back in Nov. Sorry for leaving that out.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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