This is not an easy topic to research as the HHR already has issues with brake pulsation. This was the reason I was changing the brakes, only got about 20k out of my last set before it started to wobble pretty bad during braking. I bought Raybestos rotors and Brembo pads for the replacements and put them on the same as I would with most any car. (I've changed these brakes before too). The only difference was I had the GM front backing plates to install (the ones that shield the inner rotor face from debris) and put those on behind the hub-everything went smoothly until the road test. Currently the vehicle is not drivable. During braking the entire vehicle shakes during braking-much much worse than before the brakes were changed. It is so bad you can't drive it. Anything over 30mph will rip the wheel from your hand if you apply the brakes. I've never had this happen before and I'm starting to wonder if all the shaking from the previous brakes damaged the caliper?

Only thing I could find before the sun went down yesterday was I think it's from the passenger wheel. With the front end raised and brakes slightly depressed(enough to produce drag but not enough to stop me from spinning the wheel by hand) I noticed the passenger wheel wasn't even. The brake seemed to grab about 1/4th of the rotation and the rest was easier. The driver side had even drag the entire rotation. Everything is visually intact on both wheels, I had taken everything apart twice more and made sure the caliper piston was moving freely and squarely and it appeared so.

I suppose I'll need to get a dial gauge and check runout? Any thoughts on this, any chance there's hydraulic issue or caliper issue? Thanks for any input...

 

Rear brakes adjusted? LCA bushings? Wheels torqued?

The wheels hold the rotors, so no surprise they wobble with wheel off.

 

Sounds like the wheel was not "bolted" on evenly and you have a loose wheel or the rotor wasn't bolted on correctly.

 

more like you did not seat the hub properly after you put in the inner splash shields, check the torque on the 3 bolts per side to ensure that the hub assembly is correctly seated and just double check that you removed the original spacer plate was removed, just a observation but it is the one thing you mentioned you added different from the last time you replaced the brakes.

 

Warped rotor? If not my money would be on caliper or actual brake line pressure issues. Dont know alot about the brake line pressure but would think if it has air in the lines it would cause gaps,so to speak, in the force that the calipers apply. I know it can cause pulses but to what extent, not sure.

 

Rears were not touched, I had planned to at least pull the drums and check how they're wearing but this issue has to be dealt with first. I do know the wheels were torqued correctly, I'm quite the stickler about that on all my cars. As for suspension bushings being worn out I suppose it's possible but there was no play in either wheel and the wobble is 10x worse then it was before I replaced the brakes! What I had meant by the wheels off- was off the ground. I had the front end up on stands, wheels on, suspension extended, trans in neutral and a helper gently apply the brakes until I felt drag but could also still turn the wheel by hand. This is how I can tell there's a difference and I suspect it being from the passenger side.

The old shields (can't even call them shields they're so small and seem pretty pointless) have been removed and are not double stacked. The only thing I can think of is something with the hub too. That or something stuck behind the rotor/hub face. The passenger wheel is definitely not grabbing the same as the driver's side so that's where I'll be focusing my attention first. With the amount of shaking you'd think something was seriously off and it must be I just haven't found it yet.

Thanks folks, check back in with yas after I put in some more time on her.

 

just thinking under Murphy's law! let us know how you make out with your inspection

 

Faulty adjustment of the rears is what causes most of the front problems. It's all one thing.

You did say you tried research?

 

Well the verdict is in and I am heated beyond belief. It was a bad (new) Raybestos rotor. It was warped so bad you could see the run out. Bolted the rotor to the hub with the lugs and put the caliper back on. Put the car in neutral and started to rotate the wheel with the brake not-depressed. You could sit there and watch the gap between the pad/rotor open and close, open and close with each rotation. After slapping the old rotors on it was corrected.

 

is it possible these rotors are all cast from the same "mold" regardless of the 'brand'.

I had an experience with bad new rotors too.

is it possible they are not 'tempered' properly and fail too soon?