brakes are humming...
 

Hey guys,

I am having a problem with my brakes. Every time I step on the brake pedal when the car is running, I hear this loud humming noise until I take my foot off again. Also, when my foot is off the pedal I am constantly hearing a pssht noise, like air is escaping from somewhere down near the pedals...I still have pretty good braking so I am not really sure what the problem could be. Thanks for any help.
-Randy

My '79 280ZX