TM 5-3805-281-24-1
Theory of Operation
only fully applied after the upperstructure has stopped.
Swing Motor Park Brake Applied (L): When the
The orifice and check valve is located in a block fasten
valve spool (H) is returned to neutral, pilot oil flows
to the side of the swing motor housing.
through the dig pilot pressure signal passage (E) to the
return passage causing the pressure signal to
Pilot oil pressure is maintained at the park brake
decrease. The park brake release valve spool (F) is
release valve spool (F) as long as the pilot shut-off
shifted by the spring blocking the flow of pilot oil
valve in ON. The circuit for pilot oil pressure is from
pressure to the piston (B) chamber. The oil in the
the pilot pump (H), through the pilot shut-off valve,
piston chamber flows through the orifice and check
solenoid valve manifold (D), and then to the release
valve (C) to return as the springs push the piston down
valve spool.
applying the park brake. The oil is metered through the
orifice to slow engagement to ensure that park brake is
CED,TX08227,3174
1904JUN984/4
9025
05
83
6-82