DACIA SUPERNOVA 2004 Repair Manual

30
GENERAL
30 - 4
TIGHTENING MOMENTS (daNm)
REAR
AXLE
REAR
AXLE
8,5
3,2
7,5
16
12
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GENERAL
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TIGHTENING MOMENTS (daNm)
REAR
AXLE
REAR
AXLE
1,45
8
3,2
12
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30
GENERAL
30 - 6
COMPOSITION AND DIMENSIONS OF THE MAIN BRAKING
SYSTEM ELEMENTS
Front brake
Brake caliper bore diameter F 54 mm
Aer ated bra ke disk diameter F 235 mm
The axial run out of the disk measured at Æ215 0,1 mm
Brake disk m aximum thickness 20 mm
Brake disk minimum thickness 19 mm
Braking pad thickness (support included) 14 mm
Minimal brake pad thickness (support included) 7 mm
R ear brake
Wheel braking cylinder bore diameter F 22 mm
Ne w drum diameter F 228 mm
Dr um diameter aft er grinding F 229 mm
Shoe braking lining width 40 mm
Braking lining thickness 5 mm
Minimal accepted braking lining height above rivets 0,5 mm
Master brake pump cylinder
Bore diameter 20,6 mm
Pump maximum stroke 32 mm
Brake fluid reservoir Without level alert sensor
Pressure limite r For parallel circuit
Ser vobrake master vac 7” 177,8 mm
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30
GENERAL
30 - 7
Rigid pedal: when braking,
an increased e ffort for a small
deceleration is perform ed
Ye s Replace: shaft , pedal or
servobrake fork.
Ye s
Ye s
Ye s No
No
No
No
Replace the servobrake(broken membrane)
Replace the servobrake (broken membrane)
Check:
- the integrity of the depre ssion
pipe, consequently of the retain-
ing valve;
- the sealing of the depression pipe
at the servobrake, consequently at
the vacuum pump (inlet manifold).
Is the engine
regime
changing when
braking ?
The e ngine
pedal is rig id
fro m t i me to
time ?
1
Is the connection
sh af t between
the serv ob ra k e
fork and the pedal,
grabed?
At the servobrake
entrance i s the
depre ssion the
imposed one ? I. FAILURE : RIGID PEDAL
BRAKING SYSTEM DIAGNOSTIC
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30
GENERAL
30 - 8
1
I. FAILURE : RIGID PEDAL (ctd)
On e o f th e
rigid brake
pipes is it
smashed ?
Dismount the bra ke caliper or
the brake cylinder?
Replace the corresponding
rigid pipe.
Are the brake
caliper’s pistons
or the cylinders ones correctly gliding ?
STOP
Replace the defective parts
(with Genuine Spare Parts)
Replace the brake pads,
consequently the bra ke shoes (see bellow situations).Are the brake pads,
consequently the shoes
gasket in good
condition?
The brake linings are to be replaced when
they are: -greasy
-shiny
-not in accordance with the
manufacturer ’s prescriptions (genuine Spare
Pa rts have not been used).
Ye s Ye s
No
No
No
BRAKING SYSTEM DIAGNOSTIC
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30
GENERAL
30 - 9
II.
FAILURE : LONG PEDAL
When braking, the bra ke pedal is slowly moving.
Pe rfo rm a t e st with t he st oppe d e ngi ne , a f t e r
previously performing five successive pushing on
the brake pedal (in order to vacuum the servobrake).
Locate and repair or replace the
item where a brake fluid leak is
established.
Ye s
No
Is the brake fluid
level lower
compared to the required one?
Replace the brake pump, because the pressure gas-
ket (sealing) between the primary circuit and t he
secondary circuit is defective.
STOP
BRAKING SYSTEM DIAGNOSTIC
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30
GENERAL
30 - 10
BRAKING SYSTEM DIAGNOSTIC
I. CONSTANT EFFECT TO THE PEDAL
EFFECTS
To u g h pedal:
High effort for small deceleration.
Elastic pedal
In order to di agnose, an i ncident where
the use was normal is t o be analyzed and
two tests are to be perform ed:
1. While driving the vehicle :
Interpretation tes t: pedal stroke/
deceleration rate.
2. While vehicle i s stopped, engine c ut.
Additional test of bra ke pedal press:
Pe rform five c onsecutive pressings on the
brake pedal in order to vacuum the
se rvobrake, before taking into
consideration the test re sult.
Long pedal
The test i s to be performed with stopped
vehicle and cut engine. REMARK:
It is neces sary to perform five
consecutive pressings on the brak e
peda l, in o rd er t o v a cuum t he
s ervobrake before takin g into
consideration the test result.
Floor pedal
The test i s to be performed with stopped
vehicle and cut engine.
REMARK :
Perfor m five consecutive pressings on
the brake pedal, i n order to vacuum the
s ervobrake before takin g into
consideration the test result. POSSIBLE CAUSES
- Assi stance defect
- Brake linings:
- greasy
- stacking to the disk ( non-conform )
- heating, prolonged bra king with c onstant
pedal pre ss
- Stuck piston
- Rigid duct narrowed (flattening)
- Air presence in the c ircui t: de fective
purging
- Internal leak in the braking circuit.
- Leak of fluid from reservoir (external fluid
leak from braking circuit).
Automatic adjustment : ha nd brake c able too
tighten. - Important and asymmetric wear of the
b rake linings
- St roke too ample between the servobrake
pushing rod and the brake pump
- Brake fluid having high temperature.
- Hydraulic leak (check the sealing of
the braking system components)
- Sealing gaskets defects of the two
b rake pump circuits.
- Brake fluid having high temperature
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GENERAL
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BRAKING SYSTEM DIAGNOSTIC
II.
CONSTANT EFFECT AT BEHAVIOUR
EFFECTS
Brakes not accomplishing the
required braking distance
Vibrating brakes
When braking, the vehicle ( front
p art) is left/right deviating
Braking
Heating brakes POSSIBLE CAUSES
- No n- un if o rm wo rn brake lin ings
(backing off);
- Brake linings slightly greased;
- Springs with modified characteristics.
- Brake disks with high wobbling;
- Inconstancy brake disks width;
- Particles abnormal deposit on brake disks
(oxidation between linings and disk).
- Front axl e suspension, steering (to be
checked);
- Stuck piston;
- Tires – wear, inflati on pressure;
- Rigid duct narrowed (flattening).
- Stuck piston;
Automatic adjustment : hand brake cable very
tighten.
REMARK :
Automatic recovering is performed by
means of the brake pedal, if there is no ab-
no rm al t ensi on in the hand brake cable
when released (hand brake released).
- Return spring.
- Insufficient hydraulic stroke of the brake
pump, not allowing the return at rest of
the brak e pump pistons ( brake pump
remaining under pressure);
- Stuck pistons or hardly returning;
- Rigid duct narrowed (flattening);
- Def ective adjustment of the hand brake
control.
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GENERAL
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BRAKE CONNECTIONS AND SEWERAGE
The sewera ge connection between the brake pump, bra ke calipers, pressure limiter is
performed by m eans of the t hreaded connections with METRIC PITCH.Therefore it is
important to use onl y original spare pa rts, recommended in the Spare Parts Catalogue,
specific for this type of ve hicle.
Spare parts identification
The cupping shape of the steel ducts (A)
The shape of the thre aded lengths on
parts (B)
Connections of ducts (C)
A
B
C
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GENERAL
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BRAKE FLUID
PERIODICITY OF THE BREAK FLUID CHANGE
The manufacturing conception of the brakes equipping the Dacia vehicles, especially
the di sks brake type (F 54 inner empty pistons, low qua ntity of fluid in t he c ylinders,
sliding calipers avoiding existence of a fl uid reserve in the less cooled area of t he wheel)
enable t he m aximum re jection of fluid vapori zation ri sk, even in c ase of intensive using of
brakes (mountain are a). The current bra ke fluids are subject in all cases to a slight degradation during the fi rst
months of use by a slight humidity absorpt ion seri es (see the Vehicle Warra nty and
Maintenance Booklet, for brake fluid change)
LEVEL COMPLETION
The wear of brakes pads and shoes generate a gradually diminution of brake fluid level
in its reservoi r. It is useless t o compensate t his diminution, because the level will be re -
stored in the moment of next changing the brake pads and shoes. Obviously, in the mean-
time, the level of brake fl uid in re servoir must not go down bellow the minimal mark.
HOMOLOGATED BRAKE FLUIDS
The mixture i n t he bra king circuit of two non compatible brake fluids may leads to loss
important risks mainly due to gasket damage
In order t o avoid such risks, it is obligatory t o use bra ke fluids checked and approved by
our laboratories and which are accordi ng to Norm SAEJ 1703, DOT 4.
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