I was driving my girlfriend's RS-auto. When I brake hard to a stop, the front make this belt-spinning noise while I was braking. It sounds as like the a belt slowing down to a stop due to power loss or something? I've checked her brake pads and it's fine...any clue to what's happening? thanks...

 

Please clarify.

Front what?

Belt squeal?

Your belts ARE slowing down as you usually take your foot off the gas to brake,
and braking reduces engine revs when the car is in gear.

A rapid change in RPM could certainly induce belt squeal.

Check the belt tension.