WHILE DRIVING 30 MPH AND ATTEMPTING TO STOP BRAKES FAILED. AS A RESULT, VEHICLE CRASHED INTO FOUR OTHER VEHICLES. UPON IMPACT,EST DUAL AIR BAG DID NOT DEPLOY TO IT'S FULL CAPACITY. NO INJURIES WERE REPORTED. *AK........THERE WERE NO SKID MARKS ONLY AFTER THE EQUINOX MADE CONTACT WITH OTHER VEHICLES. THE TRANSMISSION DROPPED TO THE STREET AFTER IMPACT, THOUGH THE VEHICLE WAS NOT STRUCK FROM BEHIND. THE RIGHT WHEEL ON PASSENGER'S SIDE CAME OFF. ALSO, THE SHERIFF ON THE SCENE ACKNOWLEDGED THAT THERE WAS NO BRAKE PEDAL AFTER THERE WAS ACCESS TO THE VEHICLE.*AK