i have a 95 jeep cherokee front brakes holding and getting hot to the point of smoking.have changed calipers ,when this starts to happen the brake pedal gets higher every time pressed until it is completly at top,also noticed that ocassionaly there is a pop that you can hear and feel when pedal is pressed.

 

master cylinder fault??

 

Pull off your brake hoses 1 at a time and press the brake to see if your line has collapsed . If fluid comes out then check your lines 1 at a time the same way. If fluid comes out of all your lines then your master cylinder is probably bad. Good luck.