i5.  VEHICLE BRAKES UNEVENLY, BRAKES PULL TO ONE SIDE OR GRAB (CONT) TM 9-2320-365-20-2 2-1682          Change 1             KNOWN INFO              6.            TEST OPTIONS                REASON FOR QUESTION     If vent hose is plugged, brakes will not apply on affected side of vehicle. Is vent hose at affected wheel brake free from obstructions? Air tanks pressurized. Front wheel brake shoes OK. Front wheel brake adjustment OK. Front axle quick release valve OK. Air hose to front brake air chamber OK.        POSSIBLE PROBLEMS        Faulty front brake vent hose. Faulty front brake air chamber. Faulty load sensing valve. Contaminated rear brake shoes. Faulty rear wheel brake adjustment. Faulty relay valve. Faulty air hose to rear brake air chamber. Faulty rear brake vent hose or vent valve. Faulty rear brake air chamber(s). NO Blow vent hose clear of obstruction or replace damaged vent hose (para 11-19). YES 7.            TEST OPTIONS            Visual inspection     REASON FOR QUESTION                 KNOWN INFO              Air tanks pressurized. Front wheel brake shoes OK. Front wheel brake adjustment OK. Front axle quick release valve OK. Air hose to front brake air chamber OK. Front brake vent hose OK. Front brake air chamber OK.        POSSIBLE PROBLEMS        Faulty load sensing valve. Contaminated rear brake shoes. Faulty rear wheel brake adjustment. Faulty relay valve. Faulty air line to rear brake air chamber. Faulty rear brake vent line or vent valve. Faulty rear brake air chamber(s). NO Adjust or replace load sensing valve (para 11-10). YES Replace front brake air chamber (para 11-7). Did rear brakes lock up before front brakes during road test? If rear brakes lock up or grab before front brakes on unloaded vehicle, load sensing valve needs adjustment or is faulty. Audible and Visual inspection