2004 DACIA SUPERNOVA brake

33
REAR BEARING ELEMENTS
BRAKE CYLINDER
TIGHTENING MOMENTS (daNm)
Wheel attachment scre w 7.5
Rear wheel steeri ng knuckle nut 16
Pu rging screw 1
Brake rigid piping connection screw 1.5
DISMOUNTING
With the vehicle placed on an elevator
w ith two columns, dismount:
- the wheel;
- the drum plug;
- brake drum;
- upper spring of shoes return, using
pliers FR03.
Space the brake shoes.
Unscrew: - the rigid piping connection on the brake
cylinder by means of an open-end wrench; - the two attachment screws of the
brake cylinder on t he brake plate, loosen-
ing the connection. Check the condition of the shoes brake gas-
kets; if oi l tra ces are present, replace them.
REMOUNTING
Clean t he drums and the brake shoes as-
sembly by means of a cleaner (vacuum
cleaner) for brake. Perform in re verse order t he dismounting
operations. Purge the braking system (see chapter 38).
DEN
OMINATION CODE
Di smounting pliers for shoes return spring FR03
Plug extractor pliers RO441
SPECIAL TOOLS
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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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33
REAR BEARING ELEMENTS
BRAKE SHOES
DISMOUNTING
The re placement of brake shoes must
be performed in complete set, never mount
the brake shoes equipped with brake
linings of different brands and qualities. Dismount :
- t he brake drum ( see t he corre -
sponding paragraph); - the two m aintenance springs (R)
of the shoes with a brake cylinder rod (T). By means of the pliers FR05A the brake
cylinder pistons are immobilized. Remove t he return upper spri ng of the
shoes using the pliers FR03. Release the end of t he ha nd brake cable
off the hand brake lever.
Sw ing the adjustment lever (C) up t o t he
moment it c omes into contact with the re ar
wheel steering knuckle. Distance the shoes from the plate.
S
PECIAL TOOLS
DENOMINATION CODE
Plug extracting pliers RO441
Di smounting pliers for shoes return spring FR03
Pliers for maintaining brake cylinders pistons FR05A
TIGHTENING MOMENTS (daNm)
Wheel screw 7.5
Rear wheel steeri ng knuckle nut 16
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33
REAR BEARING ELEMENTS
BRAKE SHOES
Di smount the a uxiliary connecting rod (B)
connection from the adjustment lever (C).
Bring the adjustment lever in the initial
position. Rot a t e t he c om pre ssi on sh oe wi t h 90
degrees. Dismount the lower spring.
Remove the (front) compression shoe, then
the tensioning one. REMOUNTING
Pe rform in re verse order t he dismounting
operations.
NOTE
The adjustment of the device for the
automa tic clearance taking over, is
depending of the sp ring tensio ning
caught be tween the rear shoe and the
auxiliary connecting rod.
Measure the value H=1mm, between the
auxiliary connecting rod and the front shoe.
If the va lue H is not c orrect, replace t he
auxiliary connecting rod spring and the
shoes return springs.
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C
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33
REAR BEARING ELEMENTS
REMOUNTING
By means of a tube with the outer diameter Ö51mm and a press, mount the bearing up
to t he c onnection with the drum support surface (carefully not to da mage the sealing ri ng). Set back:
- a new lock;
- the drum on the steeri ng knuckle, previously greased with grease;
- a new nut M20 x 1.5 and tighten at the re quired moment;
- the drum plug.
A djust:
- the shoes by applying a repeated pressure on the bra ke pedal;
- hand brake (see chapter 37-“Control s”). BEARING (25 x 52 x 37)
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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 .
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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
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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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