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Lancia Thesis Factory Service Manual (2002-2009)22 · Fault diagnosis
22 · Diagnostics

Brake pedal hardening

Make
Lancia
Model
Thesis Factory Service Manual
Year
2002–2009
Section
Brakes › Brake pedal hardening
Fault diagnosisBrake pedal hardening

BRAKE PEDAL HARDENING

When the brake pedal is pressed there is a hardening in the pedal travel;

No faults relating to the malfunction of the electric parking brake are signalled.

STEPOPERATIONS TO BE CARRIED OUTTEST RESULTS
0CHECK USING DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION

Connect the Examiner diagnostic equipment to the diagnostic connector check the following at the Parking Assistance Node (N.B.A.):in errors ambient

  • that there are no faults
Move on to StepPresence of faultsContinue following the instructions in the diagnostic table
1BRAKE SERVO SYSTEM OPERATIONAL CHECKSALL OKPROBLEMS ENCOUNTEREDACTION

Check the operation of the brake servo system

Continue following the instructions in the test 3330DA Brake servo operational check

Move on to StepBrake servo system operation faultyMove on to Step
2VACUUM PIPE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the vacuum pipe: there should be no bends or damageMove on to Step1. Pipe bent1. Restore the correct geometry
2. Pipe damaged

2. Replace the damaged pipe

See in Op. 3330D24 vacuum pipe for brake servo - r+r

3SINGLE-ACTING VALVE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check that the single-acting valve is working properlyMove on to StepFaulty operation

Replace the single-acting valve

See in Op. 3330D20 one-way valve for brake servo - r+r

4BRAKE SERVO PNEUMATIC CIRCUIT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
2.4 20 V,2.0 TB,2.0 TB

In particular, check:

  • that there are no air leaks;
  • that there is no seizing or hardening of the brake servo
Move on to Step1. Brake servo leaks

1. Replace the brake servo

See in Op. 3330D04 BRAKE SERVO - R.R. - Includes separation from master cylinder (pump) - for versions with Adaptive Cruise Control (A.C.C.).

2. Brake servo operation not smooth

2. Replace the brake servo

See in Op. 3330D04 BRAKE SERVO - R.R. - Includes separation from master cylinder (pump) - for versions with Adaptive Cruise Control (A.C.C.).

4BRAKE SERVO PNEUMATIC CIRCUIT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
2.4 JTD 10V

In particular, check:

  • that there are no air leaks;
  • that there is no seizing or hardening of the brake servo
Move on to Step1. Brake servo leaks

1. Replace the brake servo/pump assembly

See in Op. 3330D02 BRAKE SERVO/BRAKE PUMP assembly - R.R.

2. Brake servo operation not smooth

2. Replace the brake servo/pump assembly

See in Op. 3330D02 BRAKE SERVO/BRAKE PUMP assembly - R.R.

5VACUUM CHECKALL OKPROBLEMS ENCOUNTEREDACTION
2.4 JTD 10V

Check that the vacuum unit is working properly

Continue following the instructions in the test 3330DB Vaccum unit operational check

In certain usage conditions, low engine revs with excessive use of the brakes, the vacuum for operating the brake servo may not be sufficient with the consequent hardening of the brake pedal. There is no point in replacing the brake servo

Move on to StepVacuum unit faulty

Replace the vacuum unit

See in Op. 3330D30 vacuum pump - r+r

6BRAKE PUMP CHECKALL OKPROBLEMS ENCOUNTEREDACTION

Check:

  • that there is no seizing in the brake pump.
  • that there is no seizing in the front brake calipers
Move on to Step1. Pump seizing

1. Replace the brake pump

See in Op. 3330C14 MASTER CYLINDER (PUMP) - R.R. for versions with A.B.S.

2. Front caliper seizing

2. Replace the front calipers

See in Op. 3310A32 FRONT BRAKE CALIPERS - R.R. - Includes bleeding air

7CHECK ON CORRECT OPERATIONALL OKPROBLEMS ENCOUNTEREDACTION

Test the vehicle before returning it to the customer, checking that the problem no longer exists.

The test is essential because the braking system is one of the vehicle's safety systems.

Parts & tools for this job For 2002 Lancia Thesis

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