WENT TO STOP AT STOP SIGN AT APPROXIMATELY 4MPH AND NO BRAKES. THE BRAKE PEDAL WENT ALL THE WAY TO THE FLOOR WITHOUT ANY RESISTANCE OR HESITATION. AS A RESULT OF THE BRAKE MALFUNCTION I REAR ENDED AN ELDERLY COUPLE IN A LEXUS. RESULTING IN DAMAGE TO THEIR REAR BUMPER PLASTIC COVER AND MORE DAMAGE WAS DONE TO MY FRONT END OF THE DEFECTIVE 200 CHEVROLET TAHOE Z71 I WAS DRIVING