Amtran Rs3505 — 96V221000
Summary
THE AIR/SPRING ACTUATED PARKING BRAKE CHAMBERS MANUFACTURED BY MIDLAND (DATE CODE 145B6K) WERE FILLED WITH THE WRONG LUBRICATION. THE IMPROPER LUBRICANT CAUSES THE SEALS WITHIN THE CHAMBER TO FAIL AND RESULTS IN LOSS OF AIR. IF AIR PRESSURE DROPS TO 55 PSI THE SPRING WITHIN THE CHAMBER WILL AUTOMATICALLY APPLY THE PARKING BRAKE.
Consequence
IF AIR PRESSURE DROPS BELOW 55 PSI AND THE OPERATOR DOES NOT HEED THE LOW AIR PRESSURE WARNING AND CONTINUES TO DRIVE, THE PARKING BRAKE WILL APPLY. THIS CAN CAUSE THE PARKING BRAKE LINING TO OVERHEAT AND PREMATURELY WEAR. WHEN THE BUS IS PARKED AND THE BRAKE APPLIED, THE PARKING BRAKE WOULD NOT OPERATE PROPERLY.
Remedy
DEALERS (OR OWNERS) WILL INSPECT THE BRAKE CHAMBERS FOR THE SUSPECT DATE CODE. IF THE CHAMBER HAS THIS CODE, THE PARKING BRAKE CHAMBER WILL BE REPLACED.