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AXLE INSPECTION
Front Axle
Maintaining the front axle alignment to
specifications is very important. A qualified
technician should check and maintain the
alignment.
Regular inspections should include:
•
Toe-in inspection and adjustment (if
necessary), particularly with radial
tires.
•
Checking for proper tightness of axle
mounting U-bolt nuts, attaching or
mounting bolts and nuts.
•
Checking the axle for damage, binding,
worn parts and adequate lubrication.
•
Checking the kingpins for excessive
wear. Also, perform this check during
other scheduled maintenance, for
example as tire rotation or service,
wheel bearing service and alignment.
See the workshop manual for proper
procedures.
Toe-in
It is essential to maintain correct toe-in
and tire pressure for optimum tire wear.
Inspecting steer axle tires in the first
3,000 10,000 mi (5,000 16,000 km)
generally shows if tires are wearing
normally.
Rapid outside shoulder wear on both tires
indicates too much toe-in.
Rapid inside shoulder wear on both tires
indicates too much toe-out.
In P&D-type service, there can be a
left-to-right steer tire tread life differential
up to 40% depending on routes and other
variables.
2025 F-650/750 (TBC) , enUSA, Edition date: 202310, First-Printing
Maintenance
Follow the tire manufacturer's
recommended cold inflation pressure for
the tire size, load range (ply rating) and
steer axle loading typical for their operation
(each steer axle tire equals ½ steer axle
loading).
Special applications may warrant a setting
based on experience with the type of tire
operating loads and conditions. Radial tires
are more sensitive to toe-in setting than
bias ply tires. Fine tuning school bus
alignment to line-haul truck standards
does not drastically improve tire tread life.
STEERING SYSTEM
INSPECTION
WARNING: Failure to maintain the
steering system in proper condition can
cause reduced steering ability resulting
in property damage, personal injury or
death.
Note: Have any steering problems
immediately corrected by a qualified service
technician.
Ask your service technician to examine the
steering mechanism. Only minor
adjustments may be necessary.
Regular inspections should include:
•
Checking the tie rod, drag link end
clamp bolts and ball joints for proper
tightness.
•
Checking for installation and spread of
cotter pins and tightness of nuts at
both ends of the tie rod and drag link.
•
Checking that the pitman arm (steering
arm at steering gear) mounting is tight
and locked. Check system for leaks or
hose chafing. Repair immediately, if
necessary.
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