Steering Pump And Cylinder - Cub Cadet Domestic Series 7000 Service Manual

Domestic Series 7000 Hydraulics
7.

STEERING PUMP AND CYLINDER

7.1. Two steering units have been used in domestic
Series 7000 production: one produced by Sauer/
Danfoss, and one produced by Ross (Parker-
Hannifin).
NOTE: It is normal for the spokes of the steering
wheel on an open-center hydrostatic power
steering system to change orientation with use.
There is no mechanical connection between the
steering wheel and the front wheels.
7.2. Identification: The Sauer OSPM 63 PB unit has
a round body. The Ross steering unit has a
square body. See Figure 7.2.
Sauer Steering Unit
7.3. R&R: instructions for removal and replacement
of the steering units can be found in the DASH
PANEL AND STEERING PUMP section of this
manual.
7.4. If there is a warrantable problem with the power
steering unit, it is to be replaced as a complete
unit. Cub Cadet does not stock any internal
components for the steering units.
7.5. The following set of symptoms, causes, and
solutions has been adapted from a list compiled
by Sauer-Danfoss to aid in the diagnosis of
hydrostatic steering issues. Internal steering
unit problems are described to aid technicians in
distinguishing internal steering unit problems
from problems that lie elswhere in the system.
Internal problems dictate replacement of the
steering unit.
Ross Steering Unit
Figure 7.2
• High Effort Required to Turn Steering Wheel:
Cause 1: The auxiliary pump is not supplying sufficient
fluid to the steering unit. Confirm by testing auxiliary
pump out-put.
Solution 1: Correct the problem with the auxiliary
pump.
Cause 2: The priority spool within the steering unit is
not moving, causing fluid to be directed to other parts
of the system when the steering system needs it.
Solution 2: Internal problem; priority spool.
Cause 3: The relief valve in the steering unit is stuck
open.
Solution 3: Internal problem; relief valve.
• "Motoring" Steering Wheel: rotates on its
own:
Cause 1: Bad leaf spring in steering unit.
Solution 1: Internal problem; leaf spring.
Cause 2: The relief valve is stuck open.
Solution 2: Internal problem: relief valve.
• Poor Straight Line Steering Charactersistics:
Cause 1: There is a bind in the steering column.
Solution 1: Binds may be created by angular or radial
misalignment between the steering column and the
steering unit. Binds may also be created by a lack of
axial clearance between the steering column and the
steering unit. Correct any situation that may create
friction or binding in the steering column.
Cause 2: Bad leaf spring in steering unit.
Solution 2: Internal problem; leaf spring.
• Backlash
Cause 1: Wear or play between the steering column
and the cardan shaft.
Solution 1: If the wear is in the steering column,
replace the steering column (steering shaft per Cub
Cadet IPL). If the wear is in the cardan shaft, this is an
internal problem.
Cause 2: Bad leaf spring in steering unit.
Solution 2: Internal problem; leaf spring.
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