2004 DACIA SUPERNOVA brake fluid

30
GENERAL
30 - 15
BRAKING CIRCUIT PURGING
PROCEDURE IN PARALLEL SYSTEM
1.,6. Main cylinder with I.C.P. i ncorporated
2. Left rear wheel brake cylinder
3. Right rear wheel brake cylinder
4. Caliper of front right wheel
5. Caliper of front left wheel WORKING CONDITIONS
The vehicle is on wheels.
If the fuel tank is e mpty, place on the rear bench of the vehicle one or two persons to
enable the possibility of the circ uit opening (the passing of a larger fluid flow through the
brake limiter).
CHECKING THE BRAKE SYSTEM SEALING
Af ter purging the front and rear circuits, check if t he level of brake fl uid in reservoi r is
w ithin the minim a nd m axim range, than press t he bra ke pe dal, then during about 30
seconds, no pedal displacement must be noticed.
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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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33
REAR BEARING ELEMENTS
REAR AXLE
Check and adjust the hand brake cable.
Ad just the cleara nce at t he l imi ter ope rating rod (se e chapt er 37- Bra ke l imite r
adjustment). REMOUNTING
Before remounting, grease with grease the attachment screws of the rear axle shock
absorber bottom and the chassis, consequently, the connecting screws rear a xle-c hassis. Line up the arm s beari ngs right to t he c hassis supports, mounting them without t ighten-
ing at the moment, the nuts with the screws, assembling the axle to the chassis.
Remount the springs.
Compress the axle so that rear springs bear on the tray and set back the shock absorber
inner attachment screws. Tighten at the prescribed moment the connecting screws.
Perform the dismounting operations in the reverse order.
Check the maximum allowed axial cleara nce of the bearing using a dial gauge and the
s upport RO541A.
Note
The maximum allowed axle clearance of the bearing is 0.05mm.
Mount the rear wheels, lower t he vehicle on the ground.
Refill with fluid the brake assembly.
Pu rge the braking system.
33 - 3
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REAR BEARING ELEMENTS
BRAKE CYLINDER
A djust:
- the shoes, by applying a repeated pressure to the brake pedal;
- the rear axle bearing clearance.
Mount the wheel.
Lower the vehicle from the elevator.
Pu rge the braking system (see chapter 38).
Adjust the hand bra ke.
REPAIRING
DISMOUNTING
Di smount the bra ke cylinder off the vehicle;
Di smount:
- the purging screw;
- the protection bellows;
- the Ö22 pistons assembled with the pressure ga skets.
Check the condition of the cylinder boring, any trace of wear, oxidation or scratches
implies the re placement of the assembled bra ke cylinder.
If the cylinder components are in a good condition, lubri cate them with brake fluid and
mount them in the reverse order of dismounting. Check the easy moving of the assembled pistons in the cylinder boring.
Mount the brake cylinder on the plate;
Mount the wheel brake drum .
Check the adjustment of t he hand bra ke.
Purge the braking system.
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MECHAN ICAL ELEMENTS CONTROL
37
BRAKE PUMP
BRAKE PUMP WITH PRESSURE DROP INDICATOR ( ICP ) INCLUDED
COMPONENTS
1. Assembled primary piston with gaskets
2. Assembled secondary piston with gaskets
3. Primary piston pin.
4. Secondary piston pin.
5. Primary piston return spring
6. Secondary piston return spring.
7. Purging screw
8. ICP transducer
A –A ICP assembly section
OPERATIONA. B RAKING
THE FRONT BRAKE CIRCUIT
The primary piston is controlled by the pushing rod. A part of the brake fluid under pressur e
will operate together with the spring on the secondary piston, and the other part of the brake flui d
shall penetrate through the ducts to the upper floor towards both exits leading to the front brak e
calipers.
THE REAR BRAKE CIRCUIT
The secondary piston is continuing its movement, conducting the brake fluid under pressure ,
through the ducts, to the upper floor, towards the exit to the pressure-reducing valve. During al l
this time, the linings-pistons assembly will be balanced due to the two side springs .
37 - 1
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MECHAN ICAL ELEMENTS CONTROL
37
B. DE-BRAKING
After effort ending, the two pistons resume their initial position under the effect of the retainer
springs, while the fluid is coming back and the pressure is decreasing in both circuits.
PRIMARY CIRCUIT – PRESSURE LOOSING
Lack of pressure in the primary circuit leads to the following situation :
The primary piston is a dvancing up to the pin, so is controlling mechanically the secondary
piston. The secondary piston reaches a fluid pressure that shall operate on the piston – linings
assembly moving it t o the right, opening also t he second e xit of t he rear circ uit ( the by-pass
circuit) increasing the pressure for this circuit. In this moment, by means of the transducer, the warning light on the instrument panel is on.
SECONDARY CIRCUIT – PRESSURE LOOSING
Both pump pistons go on. The caliper cylinders of the front brake shall normally operate.
The secondary piston re aches its respective pi n, but the pre ssure will decrease (due to the
failure). BRAKE PUMP
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MECHAN ICAL ELEMENTS CONTROL
37
BRAKE PUMP
Close the connection pipe between the brake fluid reservoir and clutch transmitter cylinder
by means of the MOT 453 device. Disconnect the battery.
Drain the brake fluid reservoir.
Disconnect the connection pipe between the brake fluid reservoir and clutch transmitter
cylinder.
Dismount the brake fluid reservoir off the brake pump (avoiding fluid leakage).
Dismou nt :
- the rigid pipe screws from the brake pump and mark their position;
- the two attachment nuts of the brake pump on the servobrake .
DISMOUNTING
37 - 3
TIGHTENING MOMENTS (daNm)
Rigid pipe connection 1,5
Nut attachment P.C. with servobrake 1,3
I.C.P. (pressure drop indicator) 2
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