HHR brake noise

2008 HHR SS 29k mi. In the AM, when backing the car out of the garage, I have very little brake pedal. Symptom goes away as soon as I start driving. At times, when tapping the brake while driving, I notice a ‘whistling’ which could be mistaken for the squeal of worn pads, but isn’;t audible when applying enuff pressure to slow and stop the car. Suggestions? … tia …

are these anti-lock brakes, and could that have anything to do with this? Old style brakes often had self adjusting rear drum brakes where the adjustment only took place while backing, but I dont really know about your 2008. guys?

normal noises, no worries. just squeaky dust.

thnx much for the replies. The brake dust angle makes sense. Would turning a hose on the brakes wash it away?
I had considered self adjusters for the loss of pedal while backing out in the AM, particularly since I haven’t had problems stopping or slowing. The SS has antiskid technology.
??

This to me sounds like a possible brake booster. Specifically a vacuum leak, perhaps in the check valve.

“Very little brake pedal” I take to mean that there’s little travel when pressed. The symptom would go away once you start driving and the vaccuum is sufficient to provide assistance to your braking forces.

The whistling could easily be a symptom of the aforementioned leak.