TM 9-2320-260-20
1-22. SPECIAL PURPOSE BODIES SYSTEMS OPERATION (Contd)
e. Tractor Wrecker Crane Hydraulic System Operation (M819).
The M819 tractor wrecker has a hydraulically-powered, engine-driven crane that is used for lifting
materials and freeing mired vehicles. The crane can extend from 11.5-26 ft (3.51-7.93 m) and is capable of
lifting up to 20,000 lbs (9,072 kg). Crane components are:
A CROWD CYLINDER - Hydraulically-driven piston that extends outward when crowd control
lever is pushed forward to EXTEND position, retracts when crowd control lever is pulled back to
RETRACT position. This cylinder is contained in the inner boom assembly.
BOOM LIFT CYLINDER - Hydraulically-driven, the lift cylinder raises the boom when the
B
boom control lever is pulled back to UP position and lowers boom when control lever is pushed
forward to DOWN position.
from hydraulic pump to boom lift and crowd cylinders, and swing and hoist motor to operate crane.
1.
Boom control lever
2.
Hoist control lever
3.
Crowd control lever
4.
Swing control lever
D HYDRAULIC OIL RESERVOIR - Storage tank for hydraulic oil.
E
SWING MOTOR - Located under the crane shipper support, attached to the pivot post. The
hydraulically-powered motor allows the crane to rotate left or right up to 360 in rotation.
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