Iveco Stralis AT/AD. Manual

- tyre pressure;
- wheel hub bearing clearance;
- clearance between steering tie-rod pins and levers on

stub axles;

- efficiency of shock absorbers;
- wheel rims, which must have no buckling out of tolerance.
Check the wheel geometry with the instrument 99305354.

32813

32814

32815

Figure 4

Figure 5

Figure 6

The toe-in is the result of the difference between the distances
A and B (in mm) measured on the horizontal axis of the rims,
when observing the vehicle from above.
This produces light driving and low tyre consumption.
Toe-in is positive if B is greater than A.

Toe-in will be zero if B is equal to A.

Toe-in is negative if B is less than A.

Wheel toe-in

32973

32974

Figure 7

Figure 8

Before moving on to the checks, it is necessary to make a pre-
liminary inspection of some parts of the vehicle that may affect
wheel geometry. If any trouble is found, it will have to be recti-
fied in order to avoid incorrect measurements. The checks to
make are the following:

Set the vehicle with its wheels in the position of straight-line
travel on a flat surface. Lift the rear of the vehicle and place the
boards (3) under the wheels. Lower the vehicle, brake the rear
wheels and fit on the hook (1) with the rule (2).

Lift the front of the vehicle and place oscillators (1) under the
wheels, locking them with the clamps (2).

Positioning clips and headlights

The checks and any work on the wheel geometry
must be done with the vehicle with a static load.
Periodically make sure the light clusters are set
correctly.

FRONT WHEEL GEOMETRY
(4X2 vehicles)

114

WHEEL GEOMETRY

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Press the brake pedal and lock it in position with the tool (1)
positioned against the seat, thereby keeping the vehicle braked
for the entire cycle of measurement.

Connect the plugs of the measuring unit to the transformer
and turn on the switch. Loosen the locking screw of the
measuring unit and lift the lens shield. Press the ”off centre”
button (3) for at least two seconds, five lines will appear on
the display (1).

32975

32977

32976

Figure 9

Figure 10

Figure 11

Position the self-centring clip (2), fitted with appropriate fixing
pins (1), on the rim of the wheel. Using the knob (3), lock the
clip on the wheel, checking it is properly anchored.

Fit the measuring unit (3) on the clips (1) and fasten it with the
screw (2). Repeat these steps on the other wheel.

Electronic compensation of rim eccentricity

Turn the wheel slowly by hand and project the light signal onto
the corresponding scale of the rule (5).
Measure and note down the minimum and maximum travel
of the light signal: e.g., 12 and 8.
Calculate the mean travel: 12+8 = 20:2 = 10 and position the
wheel on the mean value calculated, marking its position.
Press the ”off centre” button (3) again till the wheel toe-in LED
(2) comes on and the digital indicator (1) shows an artificial
value.
Repeat these steps on the other wheel.

Take care the laser beam does not hit anyone’s eyes:
it would severely damage their sight.

Figure 12

Figure 13

84602

Wheel alignment

Level the measuring units (3) with the spirit level (1) and lock
them in position with the screw (2).
Move the rules (4) until they are centred by the light signal
emitted by the measuring unit and note down the values given.

32979

Lower the vehicle so that the wheels, in the marked position,
rest completely in the middle of the oscillating plates, and free
these from their bases, taking out the pins (4).

WHEEL GEOMETRY

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Figure 14

Figure 15

13952

If the values are not the same, turn the wheels until the
pointers of the light signals are on two equal values (A), exactly
the mean value of the two readings made beforehand. This
produces perfect wheel alignment.

With the measuring units still level and the wheels perfectly
aligned, using the lever (1), move the lens shield.
Using the lever (2), direct the pointer of the light signal onto
the millimetre scale of the rule (3) corresponding to the
diameter of the rim.
Repeat these steps on the opposite measuring unit and read
off the value of the toe-ins given in mm on the millimetre
scales.
The algebraic sum of these two measurements must give the
required value.

The toe-in is adjusted with the transverse tie rod so
as, for each wheel, to have a toe-in equal to half the
required value.

73038

Checking wheel toe-in

32981

Figure 16

Checking wheel deviation

With the front wheels aligned with the rear ones and the
measuring units level, press the camber button (3); the LED
(2) will come on and the display (1) will show the value of the
camber, that has to be 1º.

The deviation is checked while reading the toe-in.
The partial value of the toe-in measured on the rule (3) has
to be equal to the value measured on the rule on the other
wheel.
If, however, there is a difference in these values, e.g. -2 and +3,
the total toe-in is +1 and is therefore correct, but at the same
time it indicates a deviation between the wheels (one wheel
further forward than the other) of 5 lines.
This number of lines is calculated with the algebraic sum of the
values measured: +3-(-2) = 5, or more simply by counting the
lines between the two values.
Each line corresponds to a deviation of 2 mm.
When the deviation is greater than 10 lines (20 mm), it is
necessary to make additional checks, to verify the state of the
leaf springs (whether one of these has given way, or whether
the chassis or axle are out of shape).

Checking camber

The camber is a fixed value that cannot be adjusted.
Therefore, if you find the value is not as required,
detach and remove the axle to make the relevant
checks and replacements if necessary.

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32982

32983

Figure 17

Figure 18

Still with the front wheels aligned with the rear ones, loosen
the knurled knobs (2) and reset the graduated sector (3) on
the pointer (1) of the oscillating plate.

Turn the wheels 20º inwards and press the kingpin angle
button (3) twice; the LED (2) will come on and the display (1)
will show nine horizontal lines.

32984

Figure 19

Turn the wheels 20º outwards and press the kingpin angle
button (2) again; the display (1) will show the value of the
kingpin angle that has to be 7º.

32985

32986

Figure 20

Figure 21

Without moving the wheel, press the caster button (3). The
LED (1) will come on and the display (2) will show the value
of the caster, which has to be the required value.

With the wheels turned straight, reset the graduated sectors
(5) on the pointer (2) of the oscillating plates (4).
If the steering angles to be measured are greater than 30º, it
is necessary to use the 20º mark (1) on the oscillating plate and
the corresponding one of the graduated sector as ”0º”
reference indices.
Turn the wheels to reach a required angle (internal or external
wheel angle).
Then check that the steering angle (external or internal wheel
angle) of the opposite wheel corresponds to the required
value, remembering to use the corresponding scale with the
sign shown on the oscillating plate to read off the angle.

The caster and kingpin angle are fixed values that
cannot be adjusted.
Therefore, if you find the values are not as required,
detach and remove the axle to make the relevant
checks and replacements if necessary.

WHEEL GEOMETRY

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Checking kingpin angle and caster

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Iveco Stralis AT/AD. Manual - part 206