Iveco Daily. Manual — part 305
6
WHEEL AND TYRES
D
AILY
Base - May 2004
Check pressure.
NO
YES
Tyre pressures too low; wear more accentuated on the
outsides of the tread than in the middle.
Increase tyre pressure.
NO
YES
Tyre pressure too high, with excessive wear in the
middle of the tread.
Reduce pressure.
NO
YES
Insufficient toe-in of front wheels; substantial wear on
the inside surfaces of the tread.
Check and adjust toe-in.
NO
YES
Front wheel geometry incorrect.
Restore normal wheel geometry.
NO
YES
Distortion of wheel rims causing imbalance.
If possible, repair the rims or replace; then balance the
wheels.
Tyres incorrectly fitted to rims.
Fit the tyre correctly and balance the wheel.
NO
YES
YES
2
IRREGULAR WEAR
(continues)
WHEEL AND TYRES
7
D
AILY
Rear axle out of parallel due to breakage of the leaf
spring centre pin, or springs of different lengths, or bent
springs.
Overhaul the suspension.
YES
3
VEHICLE PULLS TO ONE SIDE
Front wheels out of balance.
Balance the wheels.
NO
YES
Front tyres at different pressures.
Check pressures ensuring that both are at the correct
value.
NO
YES
Excessive difference in wear between a pair of tyres.
Replace excessively worn tyre.
YES
Excessive toe-in of front wheels; excessive wear of the
outside surfaces of the tread.
Check and adjust toe-in.
NO
YES
Turn up the spin switch (6) to the second speed and place the
balancing machine against the tyre.
While the wheel is being spun, it will be found that the
stroboscopic effect on the wheel will make the reference
mark appear stationary; the pointer of the instrument (1),
moving from the value zero, reaches a maximum value on the
scale and then returns to zero.
When the pointer has begun to fall back, withdraw the
balancing machine, turn off the spin-up switch (6) completely
and brake the motor by means of the brake lever (7).
The wheel continues to revolve due to inertia and the
reference mark made on the tyre moves; the point to which
the reference mark has moved should therefore be noted.
Read off from the instrument (1) the value shown by the
pointer, multiply it by 10, giving the value of the balance weight
to be fitted to the rim.
The front wheels can be balanced on the vehicle using the
electronic unit 99305037; this has the advantage of balancing
the wheel together with the other rotating masses.
The operation must be carried out as follows:
- raise the front of the vehicle and make sure that the
wheels are free to rotate;
- position the imbalance detector (1) under the axle close
to the wheel being examined, arranging the height so that
the spin-up wheel of unit 99305037 (2) is in contact with
the tyre; position a support stand under the opposite side
of the axle and lower the hydraulic jack;
16998
Figure 3
Figure 4
23885
Figure 5
- connect the cable (3) of the imbalance detector to unit
99305037;
- make a reference mark on the tyre by drawing a radial
mark with chalk or using a strip of gummed paper;
- turn switch (2) to the static balancing position and
sensitivity switch (4) to notch no. 5 on the graduated
scale;
- turn on switch (5) for instrument light (1) and strobe lamp
switch (8);
- turn the spin-up switch (6) of unit 99305037 to the first
speed position so as to make the wheel rotate.
16997
Fit the balance weight calculated in this way as shown in the
figure.
If during the test, the pointer of the instrument (1, Figure 4)
remains in the green area of the box, the wheel is balanced.
To correct the residual imbalance, repeat the operations
already carried out as above; depending on the new reading
of the instrument (1, Figure 4), refer to the diagram in the
figure and proceed as follows to adjust:
Figure 6
If the weight required to balance the wheel is more
than 60
÷ 80 grams, divide the weight in half and
position the two parts so formed with one half on
the inside and one half on the outside of the rim,
making sure that they are in the same position.
NOTE
8
WHEEL AND TYRES
D
AILY
Base - May 2004
STATIC WHEEL BALANCING
- If the weight is in the zone marked with the letter A, this
means that it is too light, and in that case weight must be
added as indicated by the instrument (1, Figure 4).
- If the weight is in the bottom zone marked with the letter
C, this means that it is too heavy and in that case the
weight must be reduced as shown by the measuring
instrument.
- If the weight is found to be in the zones marked with the
letters B or D, do not remove or add any weight but
instead move it 5 cm upwards in the direction of the
arrows, see Figure 6.
502510
TYRE PRESSURE
The tyre pressures must be checked with the tyres cold.
Take great care that the pressure is correct since, if it is higher
than required, a harsh ride and excessive wear of the centre
of the tread will result, while if it is lower, the load is not
distributed over the whole tread but is concentrated at either
side, causing premature wear of these areas and also damaging
the internal structure of the tyre.
Unequal pressures between tyres affects the driving stability
of the vehicle and impairs operating safety.
Tyre abnormal wear can occur in different areas of tread.
HOW TYRE BEHAVIOUR DEPENDS ON
PRESSURE
Schematic views to demonstrate how tyre behaviour and
performance depend on pressure.
Figure 7
Figure 8
Figure 9
- 40%
EFFICIENCY 40%
+ 20%
EFFICIENCY 90%
EFFICIENCY 100%
CORRECT
The value shown inside each tyre indicates the level
of pressure of the tyre, while the efficiency relates
to the life of the tyre.
NOTE
WHEEL AND TYRES
9
D
AILY
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст