TRUCK WAS ENTERING MAJOR HIGHWAY,TRAFFIC BEGINS TOO SLOW DUE TO RUSH HOUR ,SEEING THIS OCCUR I STEPPED ON BRAKES EXPECTING TO SLOW DOWN ,UNTIL I REALIZED PEDAL HAD GONE ALL THE WAY TO FLOOR,THEN I LET UP AN PUSHED TO FLOOR AGAIN-NO BRAKES NO ROOM TO GO LEFT OR RIGHT IMPACT WAS UNAVOIDABLE,IMPACTED CAR TWICE WHICH PUSHED THAT CAR INTO ANOTHER THIS TRUCK WAS SERVICED BY GM DEALER FOR TRANSMISSION COOLING LINE AND ENGINE COOLING LINES MONDAY TUESDAY AND WEDNESDAY, NO MENTION OF BRAKE LINES ISSUE, ACCIDENT OCCURRED ON FRIDAY. ALSO HAD CONTACTED GM ABOUT ORIGINAL WORK RE: POSSIBLE WARRANTY. *TR UPDATED 07/25/12 *BF THE CONSUMER HAS SINCE TRADED THE VEHICLE. UPDATED 07/31/12