TRUCK SERVICE MANUAL
FRONT AXLE
Another reason for toe-in and the most familiar,
1. To adjust the toe-in, turn the steeri steering
is that when the vehicle is being driven, the forces acting
wheel so that the gear is in the mid-position.
on the front wheels tend to make the wheels toe out.
2. Loosen the clamping bolts on the tie rod.
3. Turn the tie rod in the direction necessary to
Incorrect toe-in will result in rapid tire wear.
bring toe-in within the specified limits.
Excessive toe-in will produce a scuffing or "feather-edge"
4. Tighten the clamping bolts on the tie rod.
at the inside edge of the tire tread. Toe-out will produce
a like wear but at the outside of the tire tread.
NOTE: Always recheck toe-in after any
change in caster or camber angles or after
When attempting to determine the causes of
any alteration in tie rod adjustment.
excessive tire wear, first check king pin inclination,
camber and caster and correct, if necessary, in the order
TURNING ANGLE
named.
Turning angle is the degree of movement from a
straight-ahead position of the front wheels to either an
No change should be made in toe-in until the
extreme right or left position. Two factors of major
other factors of front wheel alignment are known to be
importance when adjusting the angle are; tire
within specifications.
interference with chassis and steering gear travel.
Turn the front wheels to the exact straight-ahead
To avoid tire interference or bottoming of the
position.
steering gear, adjustable stop screws are located on the
steering knuckles.
When setting toe-in-adjustment, the front
suspension must be neutralized; that is, all component
To adjust the turning angle, loosen the jam nuts
parts must be in the same relative position when making
and turn the steering knuckle stop screws in. Position
the adjustment as they will be in operation. To neutralize
support stands under the front axle so that the wheels
the suspension, the vehicle must be rolled forward 12 to
are off the floor. Turn the wheels to extreme right turn
15 feet. By rolling the vehicle forward, all tolerances in
until the steering gear bottoms or contact of the tire to
the front suspension are taken up and the suspension is
chassis is made. Then back off the steering wheel 1/4
then in normal operating position. Neutralizing the front
turn or back off the steering wheel until 1/2" to 1"
suspension is extremely important, especially if the
clearance is obtained between the tire and chassis. Be
vehicle has been jacked up in order to scribe the tires;
sure to check both front tires for clearance. When the
otherwise, the front wheels will not return to the normal
proper clearance is determined, back the wheel stop
operating position due to the tires gripping the floor
screw out and tighten the jam nut.
surface when the vehicle is lowered.
Repeat the same procedure on the left extreme
Actual toe-in measurements should be taken at
turn also and adjust the left steering knuckle stop screw.
hub height between the two points on the center of the
tread at the rear of the tires, Fig. 4.
TURNING RADIUS ANGLE (Toe-Out on Turn)
Turning radius angle is measured in degrees
Mark the point and roll the truck ahead so that
and is the amount one front wheel turns sharper than the
the points are in the front at hub height and measure the
other on a turn.
distance between the same two points on the tire treads.
The difference in the two measurements is the
actual toe-in or toe-out.
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