Relief Valve Pressure Check And Adjustment; Steering Proximity Switches; General; Principle Of Operation - Manitowoc Grove 5540F Service Manual

STEERING SYSTEM
RELIEF VALVE PRESSURE CHECK AND
ADJUSTMENT
Refer to page 10-5 for pressure check and pressure
adjustment instructions.

STEERING PROXIMITY SWITCHES

General

The purpose of the steering proximity switches in the
steering system is to prevent the changing of steering modes
until all wheels are aligned forward. The sensors are
positioned on the front and rear axles Figure 10-10 and are
activated when a bracket attached to the steering yoke of the
axle, is aligned with the sensor.
p1875

Principle Of Operation

The steering system electrical circuit includes two sensors
Figure 10-12 one selector switch, one relay box and two
solenoid valves. The selector switch is controlled by the
10-12
operator in the cab to select the steering modes. The relay
box, located under the instrument panel, contains relays that
control the steering mode solenoid valves.
The system is used to select one of the three steering
modes. When the selector switch in the cab is placed in
either two-wheel steer, four-wheel steer or crab steer, that
particular mode of steering is used to steer the crane. The
system, however, will not activate unless the front and rear
wheels are in or pass over the forward position. For example,
when the front wheels are not aligned forward in two wheel
steer mode and the crane must be placed in four wheel steer,
placing the steering selector switch, located in the cab, to
four wheel steer will not place the steering system in four
wheel steer mode. Turning the front wheels to forward
position or past, activates the proximity switches and
energizes the relays in the relay box, which in turn energize
the correct solenoid arrangement Figure 10-11 to put the
steering system in four wheel steer.
Steering
Sensors
FIGURE 10-10
a0761
Published 10-21-2010, Control# 198-04
5540F/YB5515 SERVICE MANUAL
Solenoid D
Crab/4WS
STEERING MODE
VALVE
Solenoid B
4WS
2WS = Solenoid "A" Energized
Crab = Solenoids "B & C" Energized
4WS = Solenoids "C & D" Energized
Solenoid C
Crab
Solenoid A
2WS
FIGURE 10-11