I have a pulsating brake problem in my '06 HHR, which persists even after I replaced front rotors and disc brake pads. Where else should I look? Could it be steering? Or wheel balance?

 

Rear brakes, LCA bushings, ball joints, struts.

Is the pedal actually moving up/down, or, is the car shuddering on braking?

This is probably the most posted problem on this site. You might try search and read about other peoples solutions.

 

Not sure, But I think it's just in the steering wheel.

 

Welcome to the site! A shake in the steering wheel whilst braking, most likely worn out lower control arm bushings or LCA bushings. I suggest you get a pair of Moog K200792 problem solvers, like the one on the left, the bushing on the right was the second OEM bushing.
Also double check the inner and outer tierod ends and ball joints!

 

Then it has nothing to do with the front brakes. And, it is not "pulsating".

 

Hey Steve.
What about the lower steering shaft ? Don't you have a picture of that part ?

 

I do, but mine shook in just driving and was real prominent on rough roads , not so much under braking, but it could be a factor

 

You guys are almost ending each others' sentences.

Like, day-um, dis is da place fo info!!!!