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30
GENERAL
30 - 17
PRELIMINARY CHECKING
Before c hecking and adjustment of the front a xle ge ometry, pe rform t he followings
operations: * The checking of tires concerning: - dimensions
- air pressure
- the state of wear;
NOTE :
The t ires must be of same t ype, with the same state of wear, ai r pressured at the
prescribed pressure.
*The check of joints: - the wear of e lastic bushings
- the steering ball joints clearance
- the wheels bearings clearance.
NOTE :
The axial clearance of the bearings must be in admissible limits. ESTABLISHING OF THE STEERING CENTRAL POINT
In order to perform a front a xle checking and adjustment, it is ne cessary t o e stablish the
centra l point in order t o avoid measurement errors.
To do that, bring the steering wheel so that device DIR 500 for steering box ra ck
blocking is enteri ng in the orifice placed at its right upper part .
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Page 255 of 933
30
GENERAL
30 - 18
PRELIMINARY CHECKING
Due to the geometr ic conception of the front axle, the modificati on of one of one-
si de angles (castor, camber, ball joint) has no major impact on the value of other side
angles (the parallelism being the one directly influenced). The m odification of t hese a ngles doe s not oc cur duri ng vehicle exploitation, but onl y as
a consequence of a vehicle accident.
It is import ant to observe the following sequence : - placing the vehicle on rotating plates;
- braked vehicle
- suspension checking for pl acing the vehicle at its free height;
- establishing the steering centra l point and steeri ng box blocking.
- attachment of the optical devices on the vehicle, observing the manufacturer
instructions.
REPARTITION CHECKING AND ADJUSTMENT
Check the “ X” dimension symmetry of
the connecting rods.
Reading of t he “ A” value on the scale.
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30
GENERAL
30 - 19
C
HECKING OF THE FRONT AXLE ADJUSTMENT
Case 1:
The symmetry dimension “X” is correct-the value “A” is equaled distributed.
Case 2:
The symmetry dimension “X” is i ncorrect-read the value “A” on e ach side, a dds it, and
calculate the avera ge value, establishing the value for each side.
Example:
Right side value : A = 16;
Left side value : A = 10;
16 + 10 = 26; 26 : 2 = 13;
Operating the steering rods tie bar, restore the same value for both sides A = 13.
In this position, lock the rotating plates at zero poi nt.
Check in the following sequence: - camber angle;
- caster a ngle;
- parallelism;
- ball joint angle.
PARALLELISM ADJUSTMENT
Loosen t he l ock nut (1) maintaining the tie
rod of steering connecting rod (2) in a fixed
position.
Act upon t he t ie rod of steering c onnecting
rod taking into account its rotation sense of
in order to obtain the convergence or
divergence and also the fact that one of its
complete rotation leads to an axial
displacement of 1,5 mm.
OBSERVATION
The opening between the wheel’s front
and rear is measured on a F=340 mm .
After obt a ining t he c orre ct pa ra llelism ,
tighten the lock nut at the required moment
of 5 daNm.
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31
FRONT BEARING ELEMENTS
31 - 6
BRAKE GASKETS
NOTE
In order to maintain the brake efficiency,
the replacement of the brake pads shall be
made only in complete kit.
Never fit brake pads of diffe rent makes
and different qualities .
DISMOUNTING
Lift t he vehicle by means of a two columns
elevator;
Dismount the front wheel;
Disconnect the wear sensor wire;
Dismou nt : - the safety of the wedges (1);
- the wedges, by sliding them.
Detach the caliper assembly from the fork
together with the flexible hose;
Remove : - the elastic blades - the brake pads
Remount :- the brake pads their places in the fork;
- the elastic blades;
- the caliper;
- the wedges and their locks.
Reconnect the wear sensor wire.
Pr ess several times the brake pedal.
Mount the wheels.
Get down the vehicle from the elevator the
ground. NOTE
It
is forbidden to push the brake pedal
after the calipers were dismounted from
the fork. If the brake pads are not fully used but
on their friction surface, especially i n the
middle pad c hannel, there are material
traces, i t i s recommended t he cleaning of
these surfaces in order to avoid the noise
when braking.
REMOUNTING
Push the c aliper pi ston by means of the
FR 500 s pecial t ool.
SPECIAL TOOLS
FR 500 Pushing piston device
FR 500
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31
FRONT BEARING ELEMENTS
31 - 7
BRAKE CALIPER
DISMOUNTING
Lift the vehicle by means of a two columns
elevator.
Dismount the wheel.
Disconnect the wear sensor wire
Drain the brake fluid from the reservoir
Remove the locks and the caliper wedges;
Unscrew the rigid duct screw from the brake
flexible hose and detach the caliper assemb ly.
NOTE
If it is necessary to dismount the
caliper fork, unscrew the two attachment
s crews M 12.
When remounting the fork, replace the
Grower washers, tighten the screws at the
r equired moment of 6.5 daNm then seal
them with FIXAMED R 58. REPAIR
ING
Dismount the protection gasket.
Extract the piston using a wooden wedge and
a compressed air source. Remove the sealing gasket from its seat in the
caliper groove by means of a steel blade. Clean with alcohol the parts, replace t he
damaged ones, mounting being performed in the
dismounting reverse order, after previously all
parts have been oiled with brake fluid.
NOTE
Before remounting to t he wheel, c heck
the sealing of the caliper assembly.
TIGHTENING MOMENTS (daNm)
Wheel nuts 7,5
Rigid duct on front flexible screw 1,5
Purging screw 1
Flexible hose - caliper 2
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FRONT BEARING ELEMENTS
31 - 8
BRAKE CALIPER
REMOUNTING
Perform the dismounting operations in the reverse order plus the following operations : - fill the caliper with brake fluid in order to facilitate the brake system purging;
- purging the brake system.
BRAKE CALIPER SEALING CHECKING
Connect to the caliper, a pressure gauge attached to a compressed air source.
P lace a wooden wedge in order to block the piston.
Create a 0,3 bars pressure in the caliper.
Dip the caliper into a vessel with alcohol.
Move the piston several times to remove the air from the sealing gasket seat.
Check the sealing of the brake caliper at various pressu res, without exceeding the pressure of 2 bars.
If the brake shows air leaks by the piston, perform at its dismounting.
Replace the piston, the ga sket, or the caliper body, as the c ase stands.
Perform again the sealing test.
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FRONT BEARING ELEMENTS
31 - 15
SP
RING ASSEMBLY AND SHOCK ABSORBER
DISMOUN T ING SPRI NG- SHOCK AB SOR B E R ASSE MB LY OFF T HE
VEHICLE
Lift the vehicle in the part where perfo rming
the dismounting. Dismo unt :
- the wheel
- the two lower a ttachment screws of
the shock absorber leg (1 ).
- the two upper a ttachment screws of
the shock absorber on the carriage body (2).
T ake out the assembly spring – shock
absorber, by pressing on the lower arm in
order to avoid the shock absorber came in
contact with the transmission bellows.
SEPARATE SPRING FROM SHOCK ABSORBER
Place t he shoc k absorbe r on t he shoc k
absorber support (4), of the base plate (3) of
the SU S 600 device.
Place the compression plate (7) on the spring
upper catch and position t he rods gri ps (8) on
the spring lower last but one coil. Com p re ss t he sp ri ng by a l t e rna t i ve l y
tightening the nuts (9) till release it from the lower
plate of t he shock absorber. Dismo unt the upper attachment nut of the shock
absorber by means of the SUS 601 wrench.
T ake out the spring.
Place the spring on the SUS 600 de v ice shaft (2).
P ut on the shaft the lock bushing (6), the spacer (5), and tighten to the required moment t he
crank (1) till the lock bushing (6) comes into contact with the upper catch of the shock absorber.
U nscrew alternatively the nuts (9) and take out the plate (7 ) and the rods grips (8).
Release the spring by means of the crank (1) and detach from the shaft (2), the upper catch of
the shock absorber, the upper plate, a nd the spring.
1 2
2
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FRONT BEARING ELEMENTS
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SP
RING ASSEMBLY AND SHOCK ABSORBER
SP RING-SHOCK ABSORBER REMOUNTING ON THE VEHICLE
P lace the spring on the SUS 600 device shaft (2).
P osition on the spring the upper plate and the upper catch of the shock absorber.
P ut on the shaft the lock bushing (6) , the spacer (5).
Compress the spring by means of the crank (1).
Place the compre ssion plate (7) on the upper catch a nd position the rods grips (8) on the
spring last but one coil. Tighten the nuts (9) till the rods grips (2) came in contact with the spring coil.
Release the crank (1) and detach the compressed spring from the shaft (2).
P lace the shock absorber in the support (4).
P lace on the shock absorber the axial bearing, the lower plate, the buffer, and the spring.
Mount the upper attachment nut of the shock absorber by means of the SUS 601 wrench and
tighten at the required moment.
Un screw the nuts (9) and take out the plate (7) with the rods grips (8).
Mount the spring-shock absorber assembly on the vehicle in the reverse order of dismounting.
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