TM 5-2420-230-24-1
DIAGNOSIS AND TROUBLESHOOTING
IMPORTANT:
Do Not Remove The Steering Gear From The Vehicle
To properly diagnose steering complaints it is important to understand the complete steering system. Many
factors outside of the steering system will affect steering performance. Factors such as misalignment, loose-
ness in front end components, mismatched tires and dry fifth wheel, to name a few, will affect steering.
A troubleshooting checklist is provided in the Miscellaneous Section of this manual. This form can be
removed and photo copied. This checklist will follow the diagnosis outline below.
GENERAL DIAGNOSIS
Many times a steering gear is removed and disassembled needlessly because an orderly diagnostic procedure is
not followed.
A glossary of common terms is provided at the end of this section of the manual. This glossary is intended to
help you better understand the problem.
Begin your diagnosis using the following outline as a guide.
I.
DEFINE THE COMPLAINT
Talk to and question the driver - Refer to the glossary to obtain a clear understanding of what
a.
the driver is saying.
Drive the vehicle - If possible have the driver show you what he is experiencing. Drive the
b.
vehicle together to duplicate the condition.
II.
PERFORM A VISUAL INSPECTION OF THE VEHICLE
Check for dry fifth wheel - Lack of lubrication will tend to steer the vehicle.
a.
Check tires for mismatch, improper inflation or uneven wear patterns.
b.
Check for poor loading practices - Special body or equipment installations should be checked
c.
for their effect on steering performance.
Check for suspension sagging or shifting - Out of line rear axles will tend to steer the front end
d.
of the vehicle.
III.
INSPECT MECHANICAL COMPONENTS
Check all front axle components for wear, looseness or seizing.
a.
Inspect steering column for drag - more than 10 inch pounds of drag measured with the column
b.
suspended at the angle of operation is excessive.
Check steering gear mounting to be sure that it is tight. A steering gear that is shifting on the
c.
frame will affect steering performance.
IV.
CHECK THE HYDRAULIC SUPPLY SYSTEM
Follow the procedures as outlined in the hydraulic diagnosis section of this manual. Oil pressure
a.
and flow must be within the vehicle manufacturer's specifications.
HYDRAULIC DIAGNOSIS
The Sheppard M-Series integral power steering gear is a reactionary part of the power steering system. By reac-
tionary we mean that its operation is dependent on the proper supply of oil pressure and flow from the hydraulic
supply pump.
K-17
