What would cause my brakes to hiss when applied? on 2010 Ford Fusion

It started early today when I was half way to work. The brakes still work the same and the sound seem to have stopped??????

by in Rosedale, MD on October 20, 2012
2 answers
ANSWER by , October 20, 2012
booster is leaking and must be replaced. Roy
ANSWER by , October 20, 2012
Wear sensors on brake pads touching rotor , makes noise like 'fingernails on a chalkbord' . If that more closely describes the noise , then have your brakes inspected , if the wear sensor broke off (pad(s) almost metal-to-metal) , might damage rotor(s).