anyone knows what it means when your brakes pop and click?

 

but if it's the same thing as mine..I get a weird popping feeling (almost like the brakes aren't grabbing correctly) but this only happens when my AC is on or first thing in the manana when I'm sitting at a light & my car is still warming up (both times idle being slightly high...around 800 - normally at idle the car is around 600 & I don't seem to notice it then - as much). Any ideas on that?

 

generally happens when the brake pads are not installed correctly..pad shifting. when the pad shifts they would make a slight pop noise...basically it need new shims and hardware.
Dan