OK guys, help me out. I put new front disk brakes on my 55 about a year ago,and have had no problem untill recently. when i first put on my brakes the pedal is normal, but then the next time i have less of a pedal untill the pedal is to the top and the brakes start locking up. something is not releasing. could it be my master cylinder? something is stopping the piston in the calibers from releasing. any advise?