The use of the tank vehicles in the Army is increasing because of the need for larger volumes of bulk fuels
and rapid, uninterrupted distribution requirements for refueling military aircraft and vehicles.
PART A - TANK TRUCKS
The Army utilizes several different tank vehicles for use in refueling operations. Below is a description of
these vehicles and their typical uses.
M49A2C Tank Truck. The M49A2C tank truck is mounted on a modified M45A2 chassis (2 1/2 ton).
The truck has a multi-fuel engine with single front and rear dual tires. It is about 23 feet long, 8 feet wide and
7 2/3 feet high. TM 9-2320-209-10 (Operator's Manual for Truck, 2 1/2 ton 6x6 Gasoline Engine Models)
gives details on this truck. The tank body is a stainless steel 1,200-gallon tank shell divided into two 600-
gallon compartments. Each compartment has a manhole cover. One each five-pound carbon dioxide fire
extinguisher is mounted on the left and right front of the vehicle. The rear equipment cabinet consists of a
manifold, pump, filter/separator, discharge valve control and meter, water separator chamber, gage stick,
grounding assembly, pump delivery line valve, gravity delivery line valve, filter/separator drain valve, and
pressure gage. The pressure differential gage measures the effectiveness of the filter/separator. When the
pressure differential between the inlet and outlet pressure is more than 20 psi, change the filter elements and
the go/no go fuses. If pressure differential between the inlet and internal is 15 psi, replace filter elements
only. Change only the go/no go fuses when the pressure differential reading is 15 psi between the internal
and the outlet. A power take off shifting lever is located in the cab to the left side of driver seat. It operates
the pump. The lever is moved backward to ENGAGE the pump. To DISENGAGE the pump, pull lever
forward. The M49A2C is used for top and bottom loading, defueling aircraft, and pressure discharging.
M131A5C 5,000-Gallon Semitrailer. The M131A5C 5,000-gallon semitrailer (Figure 4-1) is the most
commonly used fuel servicing tank semitrailer in the Army. It has 5,000-gallon capacity and weighs 12 tons.
The entire vehicle is about 31 feet long, 8 feet wide, and 9 feet high. It is towed by a 5 ton, 6x6 tractor truck
or like vehicle that has a fifth wheel. The semitrailer is used to carry and transfer fuel, service containers,
and refuel ground vehicles. The semitrailer can travel cross-country at a reduced payload of 3,300 gallons
(1,650 gallons in each tank compartment). It can fill or empty 3,000-, 10,000- or 50,000-gallon collapsible
tanks. The vehicle can transfer product to or receive it from the fuel system supply point (FSSP). The
stainless steel tank body is divided into two 2,500-gallon compartments, has a 20-inch manhole and filler
cover assembly, with a vent valve and locking device, a discharge valve with screw assembly, and a drain
pipe. A full marker gage that indicates when the tank is full is welded to each manhole cover. There is a
walkway on top of the tank body with a slip-resistant steel grating. A ladder at the rear of the vehicle gives
access to the manhole covers. The two compartments are connected by piping to the vehicle's fuel delivery
system. There is one equipment cabinet and a filter/separator on the curbside of the vehicle. The curbside
equipment cabinet houses an auxiliary engine, pump, and battery. There are three hose tubes and one
equipment cabinet on the roadside of the vehicle. The roadside equipment cabinet houses a meter, a 1 1/2-
inch (0-55 GPM) dispensing assembly, 2 1/2-inch (225 GPM) dispensing assembly, filter/separator pressure
gages, engine controls, fixed fire extinguisher system, portable fire extinguisher, and fuel handling controls.
The three hose tubes are located directly above the roadside equipment cabinet. They hold three sections of
suction hose and a gage stick. There is a door on both ends of the hose tubes. The auxiliary engine and
pump assembly have a 2-cylinder, 4-cycle, air-cooled gasoline engine, a self-priming centrifugal pump and a
24-volt battery. The choke is on the left side of the engine. The engine controls are on the instrument panel
located in the roadside equipment cabinet. These controls consist of a power panel switch, starter button,
ignition switch, oil pressure, and voltage gage. The pump is connected to the auxiliary engine by bearing
mounted shaft. A firewall separates the two items. The entire pumping system has a total capacity of 225
GPM. The filter/separator has three filtering stages. In the first stage 15 filter elements remove solid
contaminants and coalesce any water in the fuel. In the second stage, five canisters separate the water from
the fuel and let it drain into the filter/separator sump. Finally, there are 15 go/no go fuses as safety devices
to shut off the flow of fuel if the other two stages allow water or solid contaminants to exceed a safe level.
There are three of these fuses in each of the second-stage canisters. Other parts of the filter include an
automatic dump valve, a manual drain valve, an emergency shutoff control, and three pressure gages. Any
water collected in the filter/separator is removed by the automatic dump valve. This valve is operated by a