I just did my brothers back brakes because the pressure just dropped and it happened to be the rubber on the wheel cylinder was half off ( we just had an estimate to see what had to be done because i can do the work im just not that great at diagnosing so we think they did it so he would have to rush to them to get the work done.) but after the cylinder was replaced it was pretty much perfect. it still has a little sink to the pedal before they start working but its what he knew as "normal" i was wondering what the sinking was from? fluid levels are fine. all hardware,cylinders,and pads are good in the back i was going to tackle the calipers,rotors and pads on the front. so if that doesnt work anyone have any suggestions? the master cylinder did leak for a while but now for some reason its fine no more leaks it holds the pressure. any ideas? thank you