2-24
HOIST BRAKE AND HOLDING VALVE:
The hoist has an automatic brake in the gearbox and a holding valve mounted directly on
the hoist motor to hold the load. A clutch in the gearbox allows the hoist to turn freely in
the RAISE direction. The brake is pilot released in the LOWER direction and should
allow smooth stops of a load on the hoist.
PARKING BRAKE:
A spring-applied, hydraulically released brake on the transmission holds the crane on
slopes when the power is off or the park brake switch is in the ON position. If the engine
dies while the crane is in motion, the brake will automatically be applied.
BOOM SEQUENCING VALVES:
The boom sequencing valves allow the stronger second stage boom section to extend
before, and retract after, the lighter third and fourth stages. This arrangement assures
that the boom is as strong as possible. The third stage must not extend until the RCL
boom length reads 32 feet (9.7 m). The second stage must not retract until the third
stage is fully retracted. If the boom extension or retraction does not follow this sequence,
the sequencing valves need adjusting. See the maintenance instructions.
BRAKE WARNING LIGHT:
An indicator light is installed on the dash to alert the operator when the pressure is low in
the brake accumulators. The function of this light should be checked daily. See Driving
the Vehicle section on page 2-12.
W A R N I N G
Do not bypass safety devices! Each device has a specific purpose and should not
be tampered with. Death, serious injury, or property damage could result from a
safety device that is no functioning.
Courtesy of Crane.Market
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