Renault Clio: Brake servo: Check

RIGHT-HAND DRIVE

There is no "RENAULT" tool to check the braking assistance circuit.

Use a vacuum pump fitted with couplings, part numbers 7701349942 and 7700105874 with hose part number 8200027352 or 8200376245.

CHECK

I - CHECKING THE SEALS

• When checking the brake servo seal, ensure that there is a perfect seal between this and the master cylinder (A).

  If there is a leak in this area, replace the seal between the brake servo and the master cylinder (see 37A, Mechanical component controls, Master cylinder: Removal - Refitting, 37A-2).

  The brake servo seals must be checked on the vehicle with the hydraulic circuit operational.

II - CHECKING THE BRAKE SERVO

• Remove the front engine cover (if fitted to the vehicle).

D4F, and 784

• Remove:
  • the bolts (1) from the turbocharger heat shield,
  • the turbocharger heat shield (2),
  • the oxygen sensor (3) (see Oxygen sensors: Removal - Refitting) (MR 392, 17B, Petrol injection),
  • the bulkhead heat shield clips (4),
  • the bulkhead heat shield (5).

• Remove the non-return valve (6) of the brake servo (see 37A, Mechanical component controls, Brake servo non-return valve: Removal - Refitting, 37A-26).
• Connect a vacuum pump directly to the brake servo.
• Activate the vacuum pump to obtain a vacuum of 500 mbar.
• Check that the vacuum does not fall by more than 33 mbar in 15 seconds.

  If the vacuum falls by more than 33 mbar in 15 seconds, there is a leak which may be located:

  • in the non-return valve seal, in which case replace the seal (see 37A, Mechanical component controls, Brake servo non-return valve: Removal - Refitting, 37A-26),
  • in the pushrod diaphragm, in which case replace the brake servo (see 37A, Mechanical component controls, Brake servo: Removal - Refitting, 37A-32).
• Refit the non-return valve on the brake servo (see 37A, Mechanical component controls, Brake servo non-return valve: Removal - Refitting, 37A-26).

D4F, and 784

• Refit:
  • the bulkhead heat shield,
  • the bulkhead heat shield clips,
  • the oxygen sensor (see Oxygen sensors: Removal - Refitting) (MR 392, 17B, Petrol injection),
  • the turbocharger heat shield,
  • the turbocharger heat shield bolts.

III - CHECKING THE NON-RETURN VALVE

D4F or F4R or K4J or K4M or M4R

• Disconnect the non-return valve on the inlet manifold side.

K9K

• Disconnect the non-return valve on the vacuum pump side.

• Connect a vacuum pump to the end of the non-return valve.
• Activate the vacuum pump to obtain a vacuum of 500 mbar.
• Check that the vacuum pressure does not drop. If it does, the non-return valve is pierced. Replace the valve (see 37A, Mechanical component controls, Brake servo non-return valve: Removal - Refitting, 37A-26).

D4F or F4R or K4J or K4M or M4R

• Refit the non-return valve on the inlet manifold.

• Refit the front engine cover (if fitted to the vehicle).

IV - CHECKING THE VACUUM PUMP

K9K

• Connect the external vacuum pump to the engine vacuum pump.
• Start the engine.
• Check the following values:
  • 550 mbar in 5 seconds at an engine speed of 700 rpm,
  • 700 mbar in 3 seconds and 900 mbar in 5 seconds at an engine speed of 4050 rpm.
• Replace the vacuum pump if the values are different (see 37A, Mechanical component controls, Vacuum pump: Removal - Refitting, 37A-68).
• Refit the non-return valve to the vacuum pump.

READ NEXT: