E25XM E30XM E35XM E40XMS [D114]
This section has the description and repair procedures
for the steering housing and the steering control unit.
Additional information on parts of the steering system
are in the following sections: STEERING AXLE and
This section covers the steering column assembly used
on the “XM” series of lift trucks. This assembly uses a
steering control unit with hose connections on the bot-
tom of the unit. See FIGURE 4. The steering housing
has the mounts for the steering column and the steering
control unit. The steering wheel is installed on the steer-
ing column. The housing is adjustable and is held in
position by a latch. The position of the housing can be
changed for operator comfort. The steering housing is
also the mount for some control levers and the instru-
The steering system is a hydraulic system that does not
have a mechanical connection between the steering
wheel and the steering axle. The control of the steering
is through a hydraulic circuit.
If the hydraulic pump for the steering system does not
operate, steering is still possible. A check valve permits
the steering control unit to control the steering cylinder.
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 possible.
OPERATION (See FIGURE 2.)
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 steering cylinder. The
steering cylinder in the axle actuates the steering linkage
to move the steer tires. Hydraulic oil returns from the
steering cylinder to the steering control unit and then re-
turns to the hydraulic tank.
Turning the steering wheel actuates three main parts of
the steering control unit: (1) The spool fo