Dacia SuperNova (engine E7J). Manual - part 61

30

GENERAL

30 - 7

    Rigid pedal: when braking,
an increased effort for a small
deceleration is performed

Yes

 Replace: shaft, pedal or

servobrake fork.

Yes

Yes

Yes

No

No

No

No

 Replace the servobrake

(broken membrane)

 Replace the servobrake

(broken membrane)

 Check:
- the integrity of the depression
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 engine
pedal is rigid
from time to
time ?

1

Is the connection
shaft  between
the servobrake
fork and the pedal,
     grabed?

At the servobrake
entrance is the
depression the
imposed one ?

I.    FAILURE : RIGID PEDAL

BRAKING SYSTEM DIAGNOSTIC

30

GENERAL

30 - 8

1

 I. FAILURE : RIGID PEDAL (ctd)

One of the
rigid brake
pipes is it
smashed ?

 Dismount the brake 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 brake 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
Parts have not been used).

Yes

Yes

No

No

No

BRAKING SYSTEM DIAGNOSTIC

30

GENERAL

30 - 9

II.    FAILURE : LONG PEDAL

When braking, the brake pedal is slowly moving.

Perform a test with the stopped engine, after
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.

Yes

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 the
secondary circuit is defective.

STOP

BRAKING SYSTEM DIAGNOSTIC

30

GENERAL

30 - 10

BRAKING SYSTEM DIAGNOSTIC

I. CONSTANT EFFECT TO THE PEDAL

EFFECTS

Tough pedal:
High effort for small deceleration.

Elastic pedal
In order to diagnose, an incident where

the use was normal is to be analyzed and
two tests are to be performed:
   1. While driving the vehicle :
    Interpretation test: pedal stroke/
deceleration rate.
   2. While  vehicle is stopped, engine cut.
  Additional test of brake pedal press:
  Perform five consecutive pressings on the
brake pedal in order to vacuum the
servobrake, before taking into
consideration the test result.

 

Long pedal

The test is to be performed with stopped

vehicle and cut engine.

REMARK:

      I t  is  neces sary to perform five
consecutive pressings on  the brak e
pedal, in ord er to vacuum the
servobrake  before takin g into
consideration the test result.

Floor pedal
The test is to be performed with stopped

vehicle and cut engine.
   REMARK :
   Perform five consecutive pressings on
the brake pedal, in order  to vacuum the
servobrake  before takin g into
consideration the test result.

POSSIBLE CAUSES

- Assistance defect
- Brake linings:
     - greasy
     - stacking to the disk ( non-conform )
      - heating, prolonged braking with constant
pedal press
- Stuck piston

 - Rigid duct narrowed (flattening)

-  Air presence in the circuit: defective
purging
- Internal leak in the braking circuit.
- Leak of fluid from reservoir (external fluid
leak from braking circuit).

Automatic adjustment : hand brake cable too
tighten.

- Important and asymmetric wear of the
brake linings
- Stroke 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
brake pump circuits.
-  Brake fluid having high temperature