i need help . my brakes are bled , everything is in proper order , but my front brakes lockup after about 2 or 3 blocks driving . the pedal is fine , not too soft or too hard , master cylinder is a year old and has been bench bled , the booster is about 5 years old . worked just fine , but if i press the brakes several times , the fronts lock , but if i remove the vacuum to the booster , the brakes release , i'm a little confused , PLEASE HELP!!!!!!!!