AUTOCAR IS RECALLING 690 MY 2008-2009 ACX, WX AND WXLL HEAVY DUTY CLASS 8 VEHICLES EQUIPPED WITH QUICK RELEASE VALVES (QRV). THERE ARE QRV’S IN TWO AREAS OF THE VEHICLE. THE FIRST IS IN THE LIFT AXLE AIR LINES. A LEAK IN THAT QRV WOULD AFFECT THE RATE AT WHICH THE TAG/PUSHER AXLE IS LOWERED/LIFTED. THE SECOND IS IN THE PARK BRAKE AIR LINES. A LEAK IN THAT QRV WOULD RELEASE PRESSURE ON THE PARK BRAKE SPRINGS; IF THE LEAD IS LARGE ENOUGH, THE PRESSURE WILL DROP AND SET THE BRAKES ON THE REAR AXLE.