S3.50XL S4.00XL S4.50XL S5.00XL S5.50XL S5.50XLS [D004]
1600 SRM 54
This section has the description and repair pro-
cedures for the steering housing and the steering
control unit. Additional information on parts of the
steering system are in the following sections: Steer-
ing Axle 1600 SRM 451 (B024, C024), 1600 SRM
326 (D004, D019, E007, F006, G006), 1600 SRM 10
(A177, B177, C177), and 1600 SRM 71 (E008) and
Hydraulic System 1900 SRM 453 (B024, C024),
1900 SRM 333 (D004), 1900 SRM 443 (D019, E007),
1900 SRM 328 (F006, G006), and 1900 SRM 130
(A177, B177, C177).
This section has a description and the repair pro-
cedures for more than one brand of steering control
unit. See Figure 1. The units are similar in construc-
tion and operation, with hose connections on the side
at a manifold or valve block assembly. See Figure 2
or Figure 4. Some manifolds also have a relief valve.
The steering control unit is a hydrostatic unit that
is controlled by the steering wheel. The control unit
is installed in a housing or on a bracket at the cowl
and is operated by the column assembly and steering
wheel. The steering control unit has a control section
and a metering section.
The steering system is a hydraulic system that does
not have a mechanical connection between the steer-
ing 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 steer-
ing cylinder. The lift truck is difficult to steer when
the steering pump is not operating, but the steer-
ing control unit can operate the steering cylinder and
make steering possible.
The steering control unit is a rotary valve operated by
the steering wheel. See Figure 1. During the steer-
ing operation, the steering control unit controls the
direction of flow and amount of oil that flows to the