Manitowoc Grove CD3340B Service Manual page 280

STEERING SYSTEM
STEERING ORBITROL
Description
General
The steering orbitrol (Figure 10-8) provides directional
control and metering of oil for precise steering control. In the
neutral or balance position, when the steering wheel is not
turned, the IN port (P) is connected to the OUT port (T) and
oil from the pump returns to tank. See Figure 10-8. Oil is
locked in the lines by the interacting spool and sleeve.
Centering springs keep the spool and sleeve in relative
position. The spool is coupled to the steering wheel and
rotates inside the sleeve when the steering wheel is turned.
Corresponding ports in the spool and sleeve align to meter
oil from the pump into the steering circuit and also allow
return to tank. When the sleeve catches up with the spool, oil
flow is blocked to the steering cylinder lines, and the
available supply from the pump is returned to tank.
Steering Left
When making a left turn, flow from the pump enters port P
(Figure 10-8). The gerotor takes this flow and meters it to
port L (left turn). Return flow from the steering cylinders,
enters port R and is returned to tank through port T.
Steering Right
When making a right turn, flow from the pump enters port P
(Figure 10-8). The gerotor takes this flow and meters to port
R (right turn). Return flow from the steering cylinders, enters
port L and is returned to tank through port T.
Emergency Manual Steering
The gerotor (Figure 10-8) in the orbitrol permits steering, with
difficulty, when power is lost. A check valve between the IN
and OUT ports allows for recirculation of the oil to prevent
cavitation when steering without power.
10-10
Orbitrol Repair
Special Tools
A spring installation tool, is required to assemble the orbitrol.
This tool is available under part number 1900476.
Removal
1.
2.
3.
4.
Published 04/07/2015 Control # 569-00
Remove the outside cover plate (Figure 10-7) in front of
the operator's compartment.
Completely clean around the area of the steering
orbitrol.
Put tags on the lines to the steering orbitrol for
identification at installation.
Rotate the steering wheel a small amount in each
direction several times, then release to get a balance of
pressure in the steering circuit. Slowly loosen the
hydraulics lines at ports L and R to release any
remaining pressure. Disconnect the hydraulic lines from
IN and OUT ports. Put plugs and caps in the ports and
hydraulic lines.
P0100
CD3340B/YB4411
Steering Column
Steering Orbitrol
FIGURE 10-7