POWER STEERING SYSTEM
SECTION X
SECTION
X
POWER
STEERING
SYSTEM
pressure will not prevent the operator from steering the
DESCRIPTION
vehicle, although additional effort will then be required.
The steering system on this carrier is of the power assist
type, wherein steering effort is normally exerted by the
HIGH PRESSURE FILTER (46Z133)
hydraulic steering cylinders. See Figure 10-1. Operation of
The outrigger/power steering system high pressure filter
the system is as follows:
(see Figure 10-2) is located in the pump discharge line,
1. With the carrier engine running, the engine driven hy-
forward of the front solenoid valve bank. This filter should
draulic pump discharges fluid through the filter and selector
be inspected at regular intervals. When cleaning the filter,
valve to the drag link valve, and back to the reservoir. The
inspect the material trapped in the filter for metallic par-
fluid will continue to circulate until the operator exerts
ticles. Any accumulation of metallic particles may be an
force on the drag link valve by turning the steering wheel.
indication that trouble is developing within the pump. If
metallic particles are found, check the filter again within a
few days; if metallic particles are found again, remove the
NOTE
pump for inspection and repair.
The selector valve must be in the STEERING position
STEERING/OUTRIGGER SELECTOR VALVE (36Z706)
before the steering system is operational. In the OUT-
RIGGER position, only the outrigger system is opera-
DESCRIPTION
tional.
The selector valve is provided to enable the operator to
2. When the operator turns the steering wheel, mechanical
divert the hydraulic pump output to either the outrigger
motion is transmitted from the steering gear, through the
system, or to the power steering system. The valve is
drag link, to the drag link valve. This motion moves a valve
mounted at the right rear of the carrier cab.
spool in the drag link valve, directing hydraulic fluid to
REMOVAL
opposite ends of the two steering cylinders. One cylinder
piston extends and the other retracts; since the two cylinders
To remove the selector valve, proceed as follows:
are mounted in opposite directions, all of the front wheels
turn in the same direction.
1. Mark the hydraulic lines attached to the valve.
3. The drag link valve centers itself and shuts off the flow
2. Disconnect the hydraulic lines and cap to prevent the
of hydraulic fluid to the cylinders as soon as the operator
entry of dirt.
stops turning the wheel and the front wheels reach the
3. Unbolt and remove the valve from the carrier wall.
position corresponding to the steering wheel position,
4. Road shock forces on the wheels tend to mow the drag
REPAIR
link valve, but this action also mows the control valve spool
in relation to the drag link valve body, which is held by the
Repair of this valve is limited to the replacement of ring
drag link. This movement of the drag link valve body
seals. To replace the ring seal, proceed as follows (see
relative to the internal valve spool directs fluid to the
cylinder to compensate for road shock loads, and to main-
tain vehicle directional control at the steering wheel.
1. Remove the snap rings at each end of the valve spool.
5. Note that force applied to the drag link may also be
transmitted through the drag link valve directly to the steer-
2. Push the control knob in until the rear ring seal is ex-
ing arm on the front axle. Therefore, loss of hydraulic fluid
posed. Remove the rear ring seal.
10-1
