Dacia SuperNova (engine E7J). Manual - part 76

MECHANICAL 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

OPERATION

A. BRAKING

THE FRONT BRAKE CIRCUIT

The primary piston 

is controlled by the pushing rod. A part of the brake fluid under 

pressure

will 

operate together with the spring on the secondary piston, and 

the other part of the brake 

fluid

shall 

penetrate through the ducts to the upper floor 

towards 

both exits leading to the front brake

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 

all

this time, 

the linings-pistons 

assembly will be balanced 

due to the two side springs.

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MECHANICAL 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 advancing 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 to the right, opening also the second exit of the rear circuit ( 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 reaches its respective pin, but the pressure will decrease (due to the

failure).

BRAKE PUMP

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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).
Dismount :

- 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)

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BRAKE PUMP

REMOUNTING

Perform  the dismounting operations in  reverse order.
Check the length of the pushing rod , value X = 9 mm and correct if necessary.
Before remounting, check the servobrake pushing rod stroke ( min.30 mm ).
After assembling the brake with the fluid reservoir and filling with brake fluid, no leakage must

occur in the surface of separation between the two elements.

IMPORTANT
The I.C.P. transducer is mounted after the braking system purging.
ICP  sub-assembly is not reparable ( ICP – pressure-decreasing indicator)

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