TRAVELLING NORTH ON STATE ROUTE 741 WITH MY FAMILY OF 6. WE BEGAN TO SLOW FOR STOPPED TRAFFIC ON A SLIGHT DOWNHILL GRADE. AT ONCE THE BRAKE PEDAL WENT TO FLOOR WITHOUT WARNING AND WHEN I APPLIED EMERGENCY BRAKE THE BRACKET FASTENING IT TO THE FRAME BROKE AS WELL. THE TRUCK WAS GAINING SPEED WITHOUT ANY BRAKES AT ALL. I PUT IT INTO A DITCH DOING 60 MPH. IT TOOK ME 1.5 MILES TO FINALLY GET THE TRUCK STOPPED. TOOK IT TO A GARAGE THEY REPLACE ALL BRAKE LINES TWO REAR CALIPERS, MASTER CYCLINDER, AND HYDRO BOOST CANISTER. HOW DO ALL THESE PARTS FAIL AT THE EXACT SAME TIME AND THE EMERGENCY BRAKE BRACKET BREAK AWAY FROM FRAME TRYING TO STOP VEHICLE? APPARENTLY THE SIZE OF THE VEHICLE IS TO MUCH FOR THE EMERGENCY BRAKE SYSTEM TO EFFECTIVELY STOP THIS VEHICLE. I AM TOLD BY A DEALER THIS IS A FREQUENT ISSUE WITH GM VEHICLE. I AM VERY MAD ABOUT THIS INCIDENT AND PUTTING MY FAMILY AT RISK. THIS VEHICLE WAS AT CHEVROLET DEALER IN BELLEFONTAINE OHIO 11 MONTHS AGO FOR A FULL INSPECTION AND NOTHING WAS FOUND EXCEPT AN INNER TIE ROD THAT NEEDED REPLACED. HOW??? WITHOUOT PRIOR WARNING CAN ALL THESE COMPONENTS IN A BRAKEING SYSTEM FAIL AT THE EXACT SAME TIME. THERE WAS ZERO EVIDENCE OF TAMPERING AND TRUCK MILEAGE IS BELOW NATIONAL AVERAGE. MAINTENANCE HAS BEEN KEPT UP TO DATE. SERIOUSLY CONCERNED OWNER!