WAS ENTERING DRIVE-THRU RESTAURANT, GAVE ORDER, PROCEEDED TO WINDOW TO RECEIVE ORDER/PAY. NOTICED THAT UPON STOPPING AT WINDOW, BRAKE PEDAL STARTED TO DEPRESS NORMALLY, AND THEN WENT ALL THE WAY TO FLOOR. WITHIN A FEW SECONDS SMOKE STARTED COMING INTO DRIVER COMPARTMENT THRU AIR VENTS, SMOKE COULD BE SEEN COMING OUT OF ENGINE FROM UNDER HOOD. QUICKLY PROCEEDED TO MOVE VEHICLE TO EMPTY PARKING SPOT/AREA.TURNED VEHICLE OFF, EXTINGUISHED FIRE BURNING IN ENGINE COMPARTMENT. BRAKE LINE BURST SENDING BRAKE FLUID ONTO EXHAUST MANIFOLDS IGNITING ENGINE COMPARTMENT INSULATION. COULD HAVE BEEN A SERIOUS INCIDENT/FATALITY OF MY 5 YEAR OLD DAUGHTER AND MYSELF AND/OR OTHERS IF TRAVELING AT SPEED AND/OR NOT ABLE TO EXTINGUISH FIRE QUICKLY. THIS IS AN ENGINEERING DEFECT WITH A HIGH POTENTIAL TO CAUSE FATALITIES/INJURY THAT NEEDS TO BE ADDRESSED BY THE MANUFACTURER. *TR