TM 9-2320-361-10 2-27. OPERATION OF WATER TANK TRUCKS (Contd) f. Gravity Discharging the Tank Sections. (1) Park truck near water cent airier, or area to receive water. (2) Remove gravity delivery line suction valve dust cover (13). (3) Install reducer coupling (10) on gravity delivery line suction valve adapter (12). (4) Install discharge hose (7) on coupling (10). (5) Install discharge nozzle (6) on other end of hose (7). (6) Turn gravity delivry line suction valve knob (11) left, to open position. NOTE Always empty front tank compartment first, to keep load properly distributed for vehicle operation. (7) Pull compartment valve lever (3) (front tank) or (2) (rear tank) back, to open position. 2-127