DACIA SUPERNOVA 2004 Repair Manual

MECHAN ICAL ELEMENTS CONTROL
37
The tightness of the servobrake is checked on the vehi cle, with the hydraulic
circuit under operation.
Connect the vacuum meter between the servobrake and the inlet collector by means of a “ T
” type connector. The connecting hose of the vacuum meter shall be as long as possible.
Start the engine and let it idle run for 1min.
Block the air suction hose by means of the MOT 453 device.
Stop the engine.
If air suction lowers with more than 33 mbar (25Hg) in a 15 seconds period, it means there
is a loss at t he retainer valve (replace the valve) or at t he servobrake m embrane (replace t he
servobrake) Dismount the MOT 453 device
Dismount the vacuum hose
Reinstate the connection be tween t he servobrake and the inlet c ollector by m eans of the
vacuum hose. TIGHTNESS CHECKING
SERVOBRAKE
SPECIAL TOOLS
Shutter MOT 453
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MECHAN ICAL ELEMENTS CONTROL
37
AIR FILTER REPLACEMENT
DISMOUNTING
Dismount the servobrake off the vehicle.
Loosen the lock nut (E) and dismount : -the coupling fork;
- the lock nut.
Remove the washer filter F.
RE MOUNTING
Mount the new washer filter
Mount: -the lock nut;
- the coupling fork.
A djust the value L = 1 17 + 0,5 mm .
Tighten the lock nut E on the coupling fork
Mount the servobrake on the vehicle.
Purge the braking circuit. S
ERVOBRAKE RETAINER VALVE
REPLACEMENT
Th e ope rati on is pe rform e d without
dismountin g the servobrake off the vehicle.
DIS MOUNTING
Disconnect the connection of the air suc-
tion hose with the servobrake retainer valve.
Dismount the valve by rotating a nd then
pulling it. Dismount the retainer valve gasket.
RE MOUNTING
Check the state of the retainer valve gasket
and replace it if necessary. Mount the new retainer valve gasket.
Attach and mount the new retainer valve.
Connect the air suction hose.
AIR FILTER – SERVOBRAKE RETAINER VALVE
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MECHAN ICAL ELEMENTS CONTROL
37
HAND BRAKE-ADJUSTMENT
The adjustment of the ha ndbrake shall be perform with the vehicle lift on a two columns
elevator.
NOTE
The adj ustment i s obligatory performed anytime t he shoes and secondary c ables
have been replaced.
Release the control lever of the hand brake (release position).
U nscrew the lock nut (2).
Tighten the nut ( 1) until the shoes gaskets come lightly into contact with the brake drum.
The adjustment shall be pe rformed so that is insuring a hand brake l ever stroke of min.12
teeth until the blocking of the wheels.
Tighten the lock nut ( 2) at the required moment of 2 daNm.
Lower the vehicle from the elevator.
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MECHAN ICAL ELEMENTS CONTROL
37
HAND BRAKE CONTROL LEVER
DISMOUNTING
Disconnect the battery.
Lift the vehicle by means of a two columns elevator;
Release the hand brake control lever.
D etach the fork end rod by unscrew the lock nut ( 2).
Dismo unt :
- the hand brake ornament;
- the lever support with toothed part ( 3);
- the e nd shaft rod ( 4);
- the lever shaft ( 5);
- the claw shaft (6) ;
- the c law control rod ( 7).
Detach the lever.
RE MOUNTING
Gr ease the shafts with UM 185 Li 2 grease.
Perform the dismounting operations in the reverse order.
Check and adjust the adjustment if necessary.
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MECHAN ICAL ELEMENTS CONTROL
37HAND BRAKE SECONDARY CABLE
HAND BRAKE SECONDARY CABLE
DISMOUNTING
Release the hand brake control lever ( release position );
Dismount the drum;
Release the secondary cable end from the hand brake control l ever, dismount the sheathes
s tops from the brake plate ;
Dismount the rudder bar shaft.
Remove the secondary cable.
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SPECIAL TOOLS CODE
Wheel drum cover tongs Ro 441
Hub extractor Fr. 600
Dynamome ter wrench Mot 30
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MECHAN ICAL ELEMENTS CONTROL
37HAND BRAKE SECONDARY CABLE
RE MOUNTING
Gr ease the cable with UM 185 Li 2.
Perform the dismounting operations in the reverse order.
A djust the hand brake control lever stroke.
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MECHAN ICAL ELEMENTS CONTROL
37BRAKE FLEXIBLE HOSES
The SUPER NOVA vehicles are equipped with flexible hoses with copper gaskets in order
to ensure the sealing.
PRECAUTIONS IMPOSED TO BE RESPECTED WHENDIS MOUNTING – REMOUNTING A RECEIVER
OR A BRAKE FLEXIBLE HOSE
D ue to security reasons, in order to avoid brake flexible hose twisting and the risk to get i n
contact with the suspension elements, it is necessary to observe the following operations sequence.
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TIGHTENING MOMENTS (daNm)
X (caliper flexible) 2,0
Y (the attachment connection screw of the rigid pipe on the flexible) 1,5
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MECHAN ICAL ELEMENTS CONTROL
37
BRAKE FLEXIBLE HOSES
DISMOUNTING
U nscrew the connection ( 1) (wrench) of the rigid pipe on the flexible hose till the moment
when the spring (3) is relaxed, having releasing the splinted area (4) of the sustaining bed.
Unscrew the flexible from the caliper and eventually dismount the caliper.
REMOUNTING
Assemble t he caliper with the caliper fork, mount the wedges and then screw the flexible i n
the caliper, then tighten at the m oment of 2 daNm.
The flexible must be mounted when the half axle is in the position: - symmetric wheels (mounted suspension)
- train in line (straight wheels)
Position the female end of the flexible on the sustaining bed ( 5) without twisting forcing and
check if the splinted area ( 4 ) is freely coupling in the bed splints, then place back the spring (3)
and screwing the rigid pipe on the flexible avoiding twisting.
Tighten the connection screw at a moment of 1,5 daNm.
Purge the brake circuit.
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MECHAN ICAL ELEMENTS CONTROL
37
BRAKE PRESSURE CONTROLLER
Brake pressure controller, load sensitive, avoiding the rear wheels blocking.
OPERATION PRINCIPLE
The brake pressure controller enables the rear circuit pressure “ modulation “ according to
two parameters:
-the pressure value in the front circuit
- the load on the rear axle
The pressure controller is operating on the principle of pressure compensation in two enclosures,
separated by means of a ball and spring valve. The back pressure at the valve level is created by means of the forc e developed by the
continuos action compensating spring and of the control spring acting in proportion as the rear
axle load is increasing. The pushing rod is transmitting the force of the lever spring to the pressure controller piston,
which is controlling the valve ball being in the open normal position (position P 1).
BRAKING MOMENT
In the same time with pressure increase when entering in the pressure controller, this will act
upon the ball, forcing it to overcome the c ontinuos acting spring force and by uncovering the
valve hole, to facilitate the releasing of this pressure. In the braking moment, due to position
changing of the vehicle body compared to the rear axle, by means of the acting levers, the limiting
piston is moving toward the interior, reducing the fluid exist diameter, leading to the obtaining in
this way of the pressure reduction in the rear circuit.
DE BRAKING MOMENT
In the moment of fluid inlet pressure restoring ( by leg lifting from the brake pedal ), the piston
will come back in the initial position, gradually and quickly allowing the same diameter existent at
the beginning of the braking for which the valve is open ( position P1 ). 1.
Pressure controller body
2. Valve
3. Plug
4. Spring
5. Ball
6. Piston
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MECHAN ICAL ELEMENTS CONTROL
37
BRAKE PRESSURE CONTROLLER
NOTE
The brake pressure controller is not to be repaired.
DISMOUNTING
Drain the circuit, recover the fluid;
Detach the four connections (1) of the rigid pipes.
Dismount the two M6 attachment screws of the pressure controller support on the floor (2).
Remove the support together with the pressure controller from the fixing clips.
Dismount the pressure controller off the support.
REMOUNTING
Mount the pressure controller attachment screws on the support.
Attach the support-pressure controller assembly on the floor.
Mount : -control lever
- the four connection screws of the brake pipes
Purge the braking circuit and adjust the pressure controller.
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TIGHTENING MOMENTS (daNm)
Pressure controller attachment screws on support 0,58 daNm
Pipe tightening connection screws to the pressure controller 1,5 daNm
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