hi i have an impreza turbo saloon classic 97, its been doin my head in all day. The front wheel making a hising noise when i brake it does not vanish its still there until i stop so im thinking tyres on front could be bald on inside, i have not checked the tread or im thinking trackings out, could this cause this noise, its not my brakes im sure of that. My tyre pressure is correct aswell. Can any 1 help.

 

might be a stone stuck between the backplate and brake disc.