WHILE DRIVING APPROX 50MPH ON 2-LANE HIGHWAY A BRAKE LINE BURST UNDER HARD BRAKING (VEHICLE IN FRONT OF ME SUDDENLY SLOWED TO MAKE A TURN OFF THE HIGHWAY) DUE TO RUST. PEDAL WENT ALL THE WAY TO THE FLOOR AND I LOST SIGNIFICANT BRAKING POWER. THIS RESULTED IN A MINOR ACCIDENT WHERE I DENTED THE BUMPER OF THE TRUCK THAT WAS TURNING AND SIGNIFICANTLY BENT THE RIGHT END OF MY FRONT BUMPER. WAS ABLE TO CONTINUE THE TRIP THE LAST 50 MILES TO MY DESTINATION BUT BRAKING DISTANCES WERE CONSIDERABLY LONGER THAN NORMAL. TOOK IT TO A LOCAL MECHANIC WHO SAID ALL THE BRAKE LINES WERE RUSTED AND HAD TO BE REPLACED.