[Solvedish] 2011 2SS Camaro making wah-wah-wah sound and vibrations at highway speeds

[Dirty_Camaro]

[SOLVED]
Issue 1: Wah-wah-wah sound was from the front left wheel bearing. Replaced both front hub assemblies, sound went away. May have ben caused by...
Issue 2: Rear Powerstop Z26 brake rotors were faulty / unbalanced from the factory and were the cause of the vibration. Deduced this by putting the rear factory rotors back on to find the vibration mostly went away. Currently I'm looking for a solution to replace the front Powerstop rotors to see if the vibration goes away completely. Hopefully Powerstop / CardID does me a solid and gets me a replacement that is balanced/not faulty.
[/SOLVED]

Hey all,

I've lurked around here a while, but I have a sound and vibration issue that has me stumped. I'm wondering if anyone has had this issue or might know the solution.

I had a prematurely worn out brake pad on the inside of the front passenger brakes about 6 months ago. This caused some rotor damage, so I decided to change all 4 brakes and rotors for the sake of consistency. On the brake brake-in drive I noticed a vibration at highway speeds (60+ mph) that is be intermittent. Sometimes it shakes the passenger seat's head rest, steering wheel, and stick shift. Sometimes it runs smooth. It changes as I drive highway speeds. Sometimes when I slow down and get back up to speed, it helps reduce the vibration. I've noticed that if I bank right when turning, it seems to run smoother. If I bank left, it gets worse.

Just to inspect everything and to rule out brake dust not allowing the rotor to sit flush: I removed my front brakes and rotors, sprayed brake cleaner everywhere, and reinstalled everything. I have yet to check if the rotor needs to be turned or not, or if it's out of round.

My tires were worn out, so a local tire shop said that the vibration may be coming from the tires. So I replaced all 4 with a fairly inexpensive but highly rated set, but still noticed a vibration. After taking it back to rebalance the tires three times, I can optimistically assume it's not the balance job. However, I have yet to do road force balancing.

After the third time trying to balance the tires, I began to notice a wah-wah-wah rotational sound that increases in wah-wah's as the car increases in speed. This may be coincidental on this third tire trip, as it may be something else.

I do some rare spirited driving here and there. After a random inspection, I noticed a small tread groove was missing from my rear passenger tire. Maybe that's making the noise?

I also noticed that the wah-wah seems to be in sync with the vibration.

Video of the wah-wah's below at 60mph. It's hard to hear, but if you listen closely you can hear the wah-wah's change tempo as I steer.
https://photos.app.goo.gl/db9CmT2QiXT3Vi3S7

A few things to note...

What I tired to fix the problem:

• Made sure all the nuts are 140 ftlbs
• Make sure the PSI of the tires were 36 or above
• Replaced all 4 tires
• Rebalanced tires 3 times, same shop
• Went in for a new alignment, but the shop said it was already in-alignment
• Inspected, removed, cleaned, and reinstalled front brakes and rotors
• Watched some one else drive my car from another vehicle at highway speeds, didn't notice any obvious vibration issue.

What I should do but haven't done:

• Install factory rotors 1 by 1 to find out if it's a rotor issue (I don't have a jack, so I usually need to head out of town to borrow one from a family member)
• Test rotors to see if they are warped or out-of-round with an instrument
• Turn rotors just to make sure they are 100% level
• Buy better tires

Things of note:

• 2011 2SS Camaro, 55,000 miles, stock.
• Years before vibration issue I had a minor wreck to the front passenger wheel, bent control arm. Dealership repaired. No issues after.
• Years before vibration issue I had a minor wreck to the front passenger wheel, bent control arm and broken tie rod. Dealership repaired. No issues after.
• Month's before vibration issue I had a minor wreck to rear passenger quarter panel. Some suspension damage. Dealership repaired. No issues after.
• Small chunk of tread missing from rear driver side tire
• I'm not noticing any uneven tread on any of the tires yet, but they do have some grey/white dust around the outside of the tread on some of the tires after a long drive. This may be from the car swaying and vibrating after hours of driving.

I'm kinda at a loss here. Without changing all the rotors one by one to see if one is the issue, I don't really know what to do without taking it to a dealership and spending a lot of money.

Any ideas or thoughts?

[rebelyell22]

Wheel bearing

[Dogmeat]

IF it's the wheel bearing, be sure to change the inner & outer races as well!!

Be sure to change both the left and right side bearings, cuz if 1 is worn, the other
won't be far behind! AND...change the INNER and OUTER bearings (and races!)

[christianchevell]

You did not mention if your calipers were rebuilt...……….. they would be the problem many overlook on brake jobs, and the reason your inside brake pad wore on that one caliper...sticky caliper...…. And your having previously damaged the RF....not so good either as it could be that it was not totally repaired properly either time...and the tires being shot not good either...….don't know about your wah wahs...could be bearing or ?????????? rebalancing the same set of tires over and over ….you may have a bad rim....lik the one that may have been damaged from the accidents...……. You are accident prone IMO...…….

[flyinlow89]

on these the whole hub assembly gets replaced

Originally Posted by Dogmeat

IF it's the wheel bearing, be sure to change the inner & outer races as well!!

Be sure to change both the left and right side bearings, cuz if 1 is worn, the other
won't be far behind! AND...change the INNER and OUTER bearings (and races!)

[Rock-It Man]

Yup, bad bearings are loud and usually sound different depending on which way you are turning. An experienced mechanic should take your car for a test drive.

[silversleeper]

+1, wheel bearing assembly, most cars not so hard to replace. rockauto.com
front passenger wheel of course if that wasn't obvious.

[cypressh]

Going to Jump on this bandwagon and say Wheel bearings. I ve had the same situation with my car and changing the wheel bearings made the issue disappear

[Dirty_Camaro]

Thanks for the feedback and advice everyone. So I ordered two new wheel bearings and replaced both front hub assemblies (one of which was the one that was making the noise). Good news is, the noise is gone! Bad news is, the vibration is still there at highway speeds.

The vibration mostly feels like it's coming from the back, so I raised both rear tires, started the car, gave it gas, and watched the back wheels in the air. Looks like the vibration starts getting bad around 40 and 65 on the speedo. I removed both of the back tires to eliminate the rims, tires, or if there's a tire balancing issue. Turns out it still shook quite a bit. Both sides hopped up in down, shaking the car.

I also noticed at low speeds, the inside of the rotor looks off center, as if it was machined wrong. But, I'm no expert on rotor machining, so maybe they can be this way?

Here's a video: https://photos.app.goo.gl/vDRzHMqzMpS1aeeS6 (set it to 1080 to get more detail)
The first part is just a recording of more shaking in the car. The second part are the rear rotors spinning at about 65mph. The third part is showing the side and inside of the rotors looking off center.

So, at this point it could be a warped/unbalanced rotor, but the shaking neither gets better or worse when I brake at highway speeds. It also could be something with my axel or rear diff. Next step is to simply put the original rotors in the back wheels one by one to see if it changes anything.

Any additional thoughts?

[Badbubba]

Next logical step, imo, would be to inspect the passenger rear axle, wheel bearing and hub. If the minor wreck, as you state, was able to damage suspension components, it may now finally be showing up in the drive line.

[JD555]

I dont like the rotors the way the center seems to be out of round. If not balanced I would say you might have bad rotors.

[V8only]

brakes and rotors will not cause a vibration if your foot isn't on the brake pedal. Driveshafts are a very common source of vibrations. I would pull it and have the balancing and u joints checked by a shop.

[Dirty_Camaro]

Thanks again everyone for the feedback. I finally got around to my first step: swapping the back rotors with the factory ones today.

---
TLDR: Rear rotors were a vibration problem. Swapped with factory ones and it ran smooth from 0-80mph on jack stands. Took it for a test drive, still some vibration that feels like it's from the front. Might be the front rotors as the back ones seem faulty. Will contact Powerstop for a replacement as a next step.
---

I started with the rear driver side (as it seemed to be hopping the most per my last post), and "drove" the car on jacks (exactly like I did in my previous video). The vibration wasn't near as bad, but still vibrated some at 40 and 65mph. Also, I could clearly tell it was coming from the rear passenger side now, whereas before it felt like the entire rear end.

Next, I swapped out the rear passenger rotor with the factory one. I started the car and drove it on the stands again, slowly took it to 80mph and there was no vibration what so ever. Hooray!

So, based on my tests, I can say the vibration issue is coming from the Powerstop rotors. I inspected these rotors and noticed that there aren't any factory milled balancing marks on the edge like this (my factory ones do). Maybe these just missed balancing and QA missed these? I'm not sure.

Next, I put the wheels back on and took it for a test drive at 75mph on the road. The ride was much smoother. I was convinced everything was back to normal, but then a noticeable vibration slowly built up and would come and go. Much less vibration than before the rear end rotor swap, but still not the typical smooth ride I had when the car had all factory rotors. I can't say for sure, but it felt more like a front end/steering wheel vibration this time. Maybe all 4 rotors were causing vibrations this entire time and I'm just now noticing the front? Maybe a rotor vibration from the front killed my last bearing? Not sure.

I still have the Powerstop rotors on the front and I can't completely swap them out with the factory as ones to test as one rotor is shot.

Here's my working theory: Maybe all 4 rotors missed the milling process for them to be balanced. Really bizarre and unusual, but something is at least wrong with the rear rotors. Considering they were in a set, maybe they all are faulty.

With that in mind, I'm going to contact Powerstop to see if there's anything they can do in the tune of a replacement even though I bought them almost a year ago. But, I mean, there's no guarantee that the replacement set won't be unbalanced/faulty either.

In the mean time, I could pay to have the faulty grooved factory rotor resurfaced and test everything that way to completely eliminate the new rotors.

Other things I could consider until I get a replacement rotor set (also based on everyone's feedback):
-Tires were cheap, so they may have factory defects and still might need road force balancing. Or, the vibrations could have ruined the tire tread which in turn could cause a vibration (though, they look fine from a visual inspection).
-the rear axle
-wheel bearing and hub (especially since the vibration may have affected its lifespan)
-drive shaft
-u-joints

Thanks,

[Rock-It Man]

You've been very thorough and found that the rear rotors were of poor quality.

As you suspect, the next most likely problem is that the front rotors are the same. I wouldn't spend time or money on anything else until replacing these.

Note to self: never buy Powerstop rotors.