TM 9-2320-260-20
1-22. SPECIAL PURPOSE BODIES SYSTEMS OPERATION (Contd)
f. Expansible Van Liftgate Hydraulic System Operation (M820A2).
The M820A2 vehicle is used for maintenance, shop, electrical, supply, and base station operations.
The M820A2 has a hydraulically-operated liftgate for loading and unloading equipment. Driven by an
engine-powered hydraulic pump, the liftgate can lift up to 3,000 lbs (1,362 kg). Components and accessories
of the hydraulic liftgate are described as part of the following systems:
1. Hydraulic System Operation (page 1-72).
2. Mechanical System Operation (page 1-74).
1. Hydraulic System Operation.
A
OPENING/CLOSING CYLINDER - Receives hydraulic pressure from control valve and
extends to open or retracts to close liftgate.
LIFTGATE CYLINDER - Piston-type cylinder receives hydraulic pressure from control valve
B
and extends to lower or retracts to raise liftgate.
C
HYDRAULIC PUMP - Driven by the PTO shaft, it draws hydraulic oil from the hydraulic
oil reservoir, then pressurizes and directs it to the control valve.
D
HYDRAULIC OIL RESERVOIR - Stores hydraulic oil for liftgate system.
E
is not running or hydraulic pump fails to operate.
F
CONTROL VALVE - Five-port valve directs pressurized hydraulic oil from hydraulic pump
to the opening/closing and liftgate cylinders. The control valve also directs return oil from the
cylinders back to the hydraulic oil reservoir.
1-72
