J30XMT J35XMT J40XMT [F160]
The power steering system is a hydraulic system that
does not have a mechanical connection between the
steering wheel and the steer axle. The control of the
steering is through a hydraulic circuit.
The hydraulic circuit for the power steering includes a
common hydraulic tank, that is used for both the steer-
ing and other hydraulic functions of the lift truck. The
power steering pump is supplied by its own suction line.
The power steering pump directs the hydraulic oil to the
steering control unit located in the steering column
when the steering wheel is turned.
The steering control unit is a rotary valve operated by
the steering wheel. During the steering operation, the
steering control unit controls the direction of flow and
amount of oil that flows to the hydraulic steering cylin-
der. The steering cylinder actuates the steering linkage
to move the steer wheel. Hydraulic oil returns from the
steering cylinder to the steering control unit and then re-
turns to the hydraulic tank. See FIGURE 2 and
If the steering pump does not operate, a check valve per-
mits the steering control unit to control the steering sys-
tem. The lift truck is difficult to steer when the steering
pump is not operating, but the steering control unit can
operate the steering cylinder and make steering pos-
sible. See the section STEERING HOUSING AND
STEERING CONTROL UNIT, 1600 SRM 655 for
information concerning the steering control unit.
STEERING WHEEL AND COLUMN ASSEMBLY
(See FIGURE 1, FIGURE 3, and FIGURE 4)
The upper end of the steering shaft has splines for the
steering wheel. A large nut holds the steering wheel onto
the steering shaft. The horn button is the cover for the
center of the steering wheel. The lower end of the steer-
ing shaft has splines to engage the steering control unit.
The steering column covers on the steering column give
access to the steering contro