ON TWO OCCASIONS IN THE PAST WEEK MY BRAKE PEDAL HAS BECOME EXTREMELY STIFF AT LOW SPEEDS AND CAUSED THE BRAKES TO FAIL. THE FIRST INCIDENT OCCURRED AS I APPROACHED A STOP SIGN ON A BUSY CITY STREET. MY BRAKE PEDAL BECAME STIFF AND THE BRAKES WOULD NOT STOP THE VEHICLE. CAUSING ME TO ROLL INTO THE PATH OF ANOTHER VEHICLE. I MANAGED TO STOP AND THE OTHER VEHICLE AVOIDED ME. THE SECOND INCIDENT OCCURRED THIS MORNING AS I BACKED INTO MY DRIVE WAY. AS I ATTEMPTED TO STOP MY PEDAL BECAME STIFF AND THE BRAKES WOULD NOT FUNCTION PROPERLY. DESPITE STAND ON THE BRAKE PEDAL I WAS UNABLE TO STOP MY VEHICLE BEFORE IT STRUCK MY UTILITY TRAILER. THANKFULLY NO DAMAGED OCCURRED. I CONTACTED THE PARTS DEPARTMENT AT MISSION CHEVROLET IN EL PASO, TEXAS AND WAS ADVISED THE PART IS IN HEAVY DEMAND AND WILL BE UNAVAILABLE FOR 7 TO 10 BUSINESS DAYS.