BACKING DOWN A STEEP DRIVEWAY WITH MY FOOT ON THE BRAKE WORKING FINE THE FIRST SEVERAL SECONDS THEN THE BRAKE PEDAL WENT DOWN TO THE FLOOR AND CAR ROLLED ACROSS A BUSY STREET JUMPING THE CURB AND HITTING A TELEPHONE POLE AND FENCE. NO PERSON OR VEHICLE NOR MY VEHICLE WAS HIT FORTUNATELY. A POLICE REPORT WAS FILED. THE RENTAL COMPANY BROUGHT ME A NEWER EQUINOX AND THE DAY AFTER WHILE BACKING OUT OF PARKING SPACE IN HOTEL GARAGE APPLYING BRAKES THE BRAKE WENT TO FLOOR HITTING WALL AS I PUT GEAR TO NEUTRAL AND THEN INTO PARK BUT IT HAD ALREADY HIT THE WALL.