WESTANK-WILLOCK issued a recall on the SEMI-TRAILER model

THE MIDLAND AIR BRAKE SYSTEM VALVES ON THESE VEHICLES MAY EXPERIENCE FAILURE AS A RESULT OF HYDROGEN INDUCED EMBRITTLEMENT OF THE VALVE FASTENERS. VALVE FAILURE WOULD RESULT IN LOSS OF AIR PRESSURE TO THE EXTENT THAT THE EMERGENCY SPRING BRAKES WOULD APPLY AND/OR LOSS OF SERVICE BRAKE CAPABILITY WOULD OCCUR ON ONE OR MORE AXLES SERVICED BY THE DEFECTIVE VALVE. FAILURE MODE IS DEPENDENT ON THE TYPE OF VALVE WHICH FAILS (TRAILER RELAY EMERGENCY VALVE, SERVICE EMERGENCY RELAY VALVE, TRAILER SPRING BRAKE CONTROL VALVE). CORRECTION: VALVES WILL BE INSPECTED AND SUSPECT VALVES REPLACED.