939003587 - E002 CLUTCH SLIPPING

0PRELIMINARY CHECKSALL OKPROBLEMS ENCOUNTEREDACTION

  • Carry out a driving cycle simulating a hilly/urban route with frequent gear chages to heat up the clutch/engine assemblies.
Assess the problem in the following usage conditions:

  • with the vehicle speed constant in 3rd-4th speed and the engine speed about 4-5 revs max torque, accelerate the engine rapidly with the accelerator pedal fully depressed.

  • carry out departures from a standstill on a flat surface re-engaging the clutch and accelerating gradually from an initial engine speed of 1000-1500 rpm.
Carry out a departure from stationary in 4th gear releasing the clutch pedal gradually and checking for the fault: the vehicle does not move and the engine does not cut out.
Move on to Step 1
1CLUTCH LEVER TRAVEL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check, inside the engine compartment, that when the clutch pedal is pressed the clutch control lever on the gearbox completes the correct travel.Move on to Step 71. Clutch lever on gearbox travel incomplete.1. Move on to Step 2
2. Clutch pedal free play insufficient.2. Move on to Step 2
2CLUTCH PEDAL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Clutch pedal disconnected from transmission    Op. 3330B26 CLUTCH PEDAL - R+R check that the travel is free and there is no sticking or hardening.Move on to Step 3Clutch pedal clearance or hardening.Replace the pedal    Op. 3330B26 CLUTCH PEDAL - R+R
3OPERATING CYLINDER PUSH ROD SLIDING CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the clutch operating cylinder push rod travel and return in the rest position    Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R.Move on to Step 7Clutch control cylinder push rod travel incomplete.Release the clutch control cylinder from the lever and check that the latter is free    Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R.If it is free, move on to Step 4, otherwise move on to Step 7
4CLUTCH CONTROL CYLINDER CHECK (ON VEHICLE)ALL OKPROBLEMS ENCOUNTEREDACTION

  • Release the cylinder from the clutch control lever, keeping it connected to the hydraulic system.

  • Press the pedal producing the thrust pressure and check the push rod travel.

  • Using a drift, retract the push rod checking that it travels freely.
Move on to Step 7Clutch control cylinder malfunction.Remove the clutch control cylinder    Op. 1820B30 CLUTCH HYDRAULIC ACTUATOR - R.R.and move on to Step 5.
5CLUTCH CONTROL CYLINDER CHECK (WITH GEARBOX REMOVED)ALL OKPROBLEMS ENCOUNTEREDACTION
With the part at the bench, apply pressure (using compressed air) and check the push rod travel (the test mirrors what was done in the vehicle).

  • N.B.: This test is designed to ensure that the problem is due to the cylinder and not to the pipes or the pump.
Move on to Step 6Clutch control cylinder malfunction.Replace the clutch control cylinder    Op. 1820B38 HYDRAULIC CLUTCH ACTUATOR WITH COAXIAL CONTROL - R.R WITH GEARBOX REMOVED
6CLUTCH PEDAL TRAVEL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
With the system disconnected, check that the travel is correct when the pedal is pressed and released.Move on to Step 71. Hydraulic pump malfunction.1. Replace the pump    Op. 1820B20 MASTER CYLINDER (PUMP) - R + R
2. Flexible pipe from clutch reservoir to pump worn or distorted.2. Replace the pipe    Op. 1820B40 HOSE FROM CLUTCH RESERVOIR TO MASTER CYLINDER (PUMP) - R + R
3. Flexible supply pipe to clutch control cylinder worn or distorted.3. Replace the pipe    Op. 1820B56 RIGID PIPE FROM VIBRATION DAMPER TO SLAVE CYLINDER - R R
7PLATE LEVER AND BEARING CHECK (WITH GEARBOX REMOVED)ALL OKPROBLEMS ENCOUNTEREDACTION
After the gearbox has been removed, check that there is no hardening of the lever (as a result of dirt or insufficient greasing) and that the plate bearing slides freely in its housing and shows no signs of damage.The thrust bearing offset reference on the diaphragm spring may indicate that the centering is not correct.Move on to Step 81. The presence of dirt or wear due to insufficient greasing does not allow the thrust bearing to slide correctly.1. Replace the faulty or damaged components.
2. Thrust bearing not correctly centered.2. Ensure that the bearing is correctly centered.
8CLUTCH ASSEMBLY CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Visually inspect the state of the clutch assembly, making sure there are no breaks and/or signs of overheating on the plate, obvious deterioration of the driven disc or grease/oil on the friction surfaces.Measurements using the gauge as in the manual.Move on to Step 91. Obvious deterioration of the clutch disc and/or plate broken.1. Replace the assembly    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
2. Clutch plate with vitrified seal.2. Replace the clutch plate    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
3. Oil or grease on the disc.3. Remove the oil or grease on the disc.
4. Diaphgram spring broken.4. Replace the mechanism    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
8CLUTCH ASSEMBLY CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Visually inspect the state of the clutch assembly, making sure there are no breaks and/or signs of overheating on the plate, obvious deterioration of the driven disc or grease/oil on the friction surfaces.Measurements using the gauge as in the manual.Move on to Step 91. Obvious deterioration of the clutch disc and/or plate broken.1. Replace the assembly    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
2. Clutch plate with vitrified seal.2. Replace the clutch plate    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
3. Oil or grease on the disc.3. Replace the assembly
4. Diaphgram spring broken.4. Replace the assembly    Op. 1810A24 CLUTCH - R + R WITH GEARBOX REMOVED
9CLUTCH SLIDING SPLINED HUB CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the following, in order:

  • for excess grease on the clutch plate hub bushes and the gearbox main shaft;

  • the condition of the main shaft hub.
Move on to Step 10Main shaft damaged, hub worn, excess grease on the bushes.Replace the hub and/or main shaft.
10FLYWHEEL CONDITION CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the condition of the flywheel.In particular, check:

  • the state of the surface;

  • wear;

  • cuts;

  • presence of grease/oil on the disc surfaces;

  • signs of overheating.
End of diagnosis1. Flywheel damaged.1. Replace the flywheel    Op. 1024B10 ENGINE FLYWHEEL - R + R FOR VERSIONS WITH MANUAL GEARBOX
2. Presence of dust in the flywheel friction seal.2. Remove the dust from the flywheel friction seal.