slonny

I am having a some strange issues after all the repairs and maintenaces I have done on my 2011 Chevy HHR.

Passenger's side brake caliper rebuild
Brake pads changed
New LCA installed
New CV axles installed and seals replaced
New tires installed and balanced
New rear shocks installed

Service ESC message keeps popping up once in a while and then goes away. I thought I could connect a scanner and do a scan for codes when I get that message while driving. The scanner says that no codes are found.

The main issue that that I have is not that message, but vibration that I get while braking at highway speeds. There are no vibrations at all while I am traveling at any speed up to 50 mph and braking. But when I am driving on the highway at 50 mph and above I get some strange rumble when I press the brake.

Correct me if I am wrong, if one of the rotors is warped, then I should feel noticeable vibration at any decent speed. BTW, I did not resurface my rotors when I changed my brake pads. But I did not have that problem before, as well.

Any suggestion what that could be? I checked wheel bearings today while installing new rear shocks, in the front and the rear. Both are fine.

Thanks

firemangeorge

May be an ABS code related to the ESC light. Most code readers don't show ABS codes. You'll need to try a better scan tool like a Tech II.

donbrew

What about the rear brakes and all 4 hubs?

slonny

The rear brakes are fine. It was a real pita trying to get the rotor off, though. Checked all 4 wheel bearings. Shook the hell out of all 4 wheels.

Also I received a "faulty" cv axle with a shaft that would not slide into the hub all the way, so I had to knock the hub onto the shaft until I was able to thread the axle nut. Maybe I messed up something related to ABS on that hub? Although I was hitting right down the middle portion of it.

ABS is a possibility. But wait... If there are problems with ABS system, I should be experiencing them at all speeds, not only at highway speeds. As I mentioned earlier, anything up to 50 mph is fine. ABS works flawlessly. Wouldn't ABS light appear, as well, if there were problems with ABS system?

slonny

I just found this video showing exactly the problem that I am experiencing:
And now I know what to call it thanks to this thread (https://www.chevyhhr.net/forums/prob...ll-time-48247/), brake judder.
It seems that it maybe related to not adjusted rear brakes, as donbrew mentioned earlier. I didn't even know that HHRs have these problems. I have 2011 model, and I would think by then they should have taken care of it. I adjust them today and see how it goes.

I remember I spent a long time hitting those stuck rear brake drums. The pads were fine, but I never cared to adjust the brakes afterwards.

There is another thing that I think may have been an issue. A while ago I mentioned in another thread (https://www.chevyhhr.net/forums/prob...g-noise-57312/) that I was having clunking issues and that a local mechanic used a heavy duty impact wrench to tighten lug nuts and axle nuts on both sides which solved the clunking issue that I had. I really don't want to blame it on anyone, but after reading this article (Brake Rotors: When To Resurface And When To Replace -) it seems that one of the causes for rotor distortion is exactly that.

"Rotor distortion and runout also can be caused by overtightening or uneven tightening of the lug nuts. If somebody zips on the lug nuts with an impact wrench, the uneven loading of the lug nuts can twist and distort the hat section of the rotor, causing the disc part of the rotor to wobble as it rotates. Using a torque wrench to final tighten the lug nuts prevents this kind of distortion."

I looked around and it seems that resurfacing rotors will cost about $15 per rotor, whereas new economy rotors cost about $10 more. I assume brake pads (the new ones only have about 1k miles on them) also need replacement.

donbrew

"rear brakes are fine" as in brand new shoes and drums properly adjusted?

I have experienced a similar thing when I had the rears over adjusted. And when I replaced everything, when there was plenty of shoe left, I was amazed at the difference. The drums warp, too.

I suspect beating on the hub could damage the wheel speed sensor. If it was ABS causing the vibration there would be ABS and traction control lights at the same time. Usually that would cause the car to swerve not vibrate.

The ABS light needs to be on to get an error code with an ABS capable reader.

Rotors don't warp for no reason. Usually because the rear brakes are not doing their job.

Oldblue

Economy brake rotors can be a problem from the get go! Turning your rotors won't take the warp out of them , we've seen many a post that the judder is back soon after rotor turning!
Your right about the impact gun causing problems, a torque spec is stated and so it should be applied, 100 ft lbs on the lug nuts!!

firemangeorge

Did a little reading to try to learn some more about ESC. From what I gather, the ESC system sort of "piggybacks" off of the ABS system. In other words, it uses the same readings from the wheel speed sensors that the ABS uses.
So, if you had a bad reading from a speed sensor, then it could effect the ESC system. Just not sure if this bad reading could trigger only the ESC light and not the ABS one also.

Just sharing some info I read about.

slonny

What I meant by "rear brakes are fine" is that they only have a few 16th of an inch of life left and the brake rotor is worn out to its limits. :)

Max diameter on the rotor is 230.6 mm

With this in mind I am planning to order some new rotors and brake shoes. Meanwhile, I properly adjusted rear brakes. They were nowhere close to being adjusted correctly. I followed pessimism's advice to "adjust each star wheel until you get 2 spins of the wheel before it stops, with the rim/tire bolted on and you trying as hard as you can to give it a spin." I will didn't have a chance to test drive the car yet.

I will take it for a lengthy drive tomorrow and see how she feels. If I am still getting brake judder I will look into getting new rotors and brake pads. BTW, my old ones have only 1k miles on them. Can they be reused? There is still a lot of meat left on them.

Anyway, my front rotor seems to be in pretty good shape. It would be disappointing if it warped.

I have been getting those ESC messages ever since new control arm installation. After new cv axle installation they began to randomly appear and disappear from time to time. Possibly I did something to the speed sensor or wiring.

slonny

I tried to upload images to the gallery as an experiment, but can't find a way to delete them. How do I go about that?