Component: PARKING BRAKE
VEHICLE DESCRIPTION: HEAVY DUTY TRUCKS EQUIPPED WITH HALDEX MANIFOLD DASH VALVES (MDV) USED IN TRACTOR AND TRAILER PARKING BRAKES. THESE VALVES DO NOT MEET THE REQUIREMENTS OF FMVSS NO. 121, "AIR BRAKE SYSTEMS." A LOSS OF THE ISOLATION OF THE TWO BRAKE SYSTEM CIRCUITS CAN RESULT IN THE LOSS OF SERVICE BRAKES WHEN THERE IS ANOTHER FAILURE OF ONE OF THE TWO BRAKE CIRCUITS.
Consequence: THE LOSS OF SERVICE BRAKES CAN OCCUR, INCREASING THE RISK OF A CRASH.