TM 9-2320-209-10-2 Table 1-4. Operator/Crew Preventive Maintenance Checks and Services for M50A1, M50A2, and M50A3 Water Tank Trucks - Cont NOTE: These checks are to be made in the order listed, within designated interval. B-Before operation A-After operation D-During operation W-Weekly M-Monthly 2 (cont) 3 ● Left-side tank body front (1), center (2) and rear (3) mounting bolts. CONTROLS AND RELATED EQUIPMENT Monitor controls and related equipment for proper operation. Listen for unusual noises. Improper oper- ation or un- usual noises. 1-22