I believe that the problem may be caused by rust on the rotors. If you look at the rotors after a damp day, you will see signs of rusting. The rust may be worse between the pads and rotor as the pads may hold the moisture and the metal in semi metallic pads may increase the rusting. Rust will cause the pads to have more friction at the rusty areas. If it rusts worse were the pads sit the pads will have more grip when that comes around. Since the front wheels turn at different speeds when you turn a corner, the rusty areas hit the calipers at different times so the right side brakes harder at one point then the left side shortly after then right, left back and forth causing the steering shake. If they happen to get in sync, the shake goes away until you turn again.

I've had some success getting rid of it by putting slight pressure on the brakes while driving down the mile stretch of straight road before I get to my driveway to wear the rust off.

The ultimate cure would be to use a material for the rotors that doesn't rust.

 

This thread died out in 2008. But there are hundreds of others on the subject. ALL HHRs were built in Mexico. I think the TSB you mean is about the water shield that was re designed around 2009, the new part is available and can be installed easily.

Most likely causes:
Poorly adjusted/worn out REAR brakes.
Bad lower control arm bushings.
Bad wheel hub(s).

The SEARCH tool at the top center of each page works pretty good.

 

I' ve got a dutch 2006 hhr with an auto trans and 2.4 l engine.
I replaced all my brakes. Delco discs at the front , delco drums and pads at the back. And still i have a vibration in my rear brakes. When i drive about 60 mph and i slowly put the parkingbrake on it vibrates like hell..
Every part is new. Even the fluid. anyone has an idea..???

 

And i work for at a corvette/ chevrolet dealer in holland. And stil cant find a sollution.

 

Double check the rear lower control arm bushings, if these are done they will show as a shake under braking.
I have just dealt with this I have the 11.65 inch SS non Brembo rotors and stock LS calipers up front and GM drums and shoes out back. I replaced my LS LCA bushings with K200792 Moog bushing/ bearing, the two piece part on the right is my old GM bushing, 4 years old and about 65,000 miles

 

Thanks

 

I was looking for information on the HHR brake shimmy issue. I worked for GM for 21 years. They had underengineered the brakes on the HHR and I believe Pontiac G6 brakes are bigger and fit so I was looking if someone had done it and had which parts they had to buy. I will try and find out more.

 

Start by reading all of this thread and then using the SEARCH tool. Generally, there is nothing wrong with the brakes it's a maintenance problem. Self adjusters don't work well enough, rubber bushings wear out.

 

HHR 2425 , welcome to the site, larger brakes up front are readily available , read here.


https://www.chevyhhr.net/forums/brak...ard-hhr-42938/

And keep your rear drum brake shoes adjusted

 

Thanks Oldblue, thats is what I was looking for.

Donbrew, I found this message using a search, I only have so much time so I thought I would ask if anyone could help. Just so you know, I held a masters mechanic license for over 20 years and have 3 degrees. I have worked as both a technician and an engineer. This is not a maintenance issue. If the self adjusters don't work well enough, that would also be an engineering issue.