Valeoscope Commercial Vehicles Clutch 2020

Diagnosis Clutch slippage or lack of torque capacity

2. Grooves on the pressure plate friction surface made by facing rivets

3. Cracks on the pressure plate

4. Pressure plate deformed

5. Rubbing of the rivets after total wear od the facings

Parts inspection ●● There are abnormal cracks on the pressure plate friction surface. ●● The clutch is very often used in severe conditions (earth moving, refuse lorry). ●● Vehicle is often started with the inappropriate gear.

Parts inspection ●● The pressure plate surface is warped. Vehicle behavior

Parts inspection The pressure plate is grooved or worn by steel parts of the friction disc (rivets). Vehicle behaviour Clutch slippage

●● This deformation of the pressure plate may have impacted on the clutch function and can accelerate the facings wear.

Rubbing of the rivets after total wear od the facings

Parts inspection ●● The facings are fully worn up to the rivets head. ●● The facings thickness or clutch disc thickness under load are below specifications. Vehicle behavior ●● The clutch slips at any time. Reasons ●● Normal conditions: The clutch life's limit has been reached in normal vehicle usage (long haul, urban, off road). ●● Facings wear too fast: Wrong conditions or wrong adjustments of the clutch linkage system. Seizing of the release bearing on the tube-guide due to extreme conditions or to wrong driving habits. Vehicle startup in abnormal conditions. Diagnosis ò ò Check if the facing wear capacity limit has been reached by using wear sensors if available. Attention Ɂ Ɂ Always start the vehicle in first gear to protect the clutch. Keep watching wear indicators. Advice   Replace the 3 parts of the clutch kit.  Adjustments must be done according to the manufacturer’s instructions.

Pressure plate deformed

Reasons ●● When the deformations are serious, they should become incompatible with the cushion capacity of the clutch disc. ●● The lack of progressivity results in a lack of torque capacity and the facing wear is accelerated. ●● When deviation from the facings and the pressure plate exceeds 1 mm, the contact between the facings and the pressure plate is only on the inner diameter. This generates slippage. Diagnosis ò ò Important heat dissipation in clutch during vehicle startup (road grade, vehicle loads…). ò ò The deformation of the pressure plate is due to the important thermal flow (convex shape when hot, concave shape when cold). Attention Ɂ Ɂ Check the deformation amplitude by using a ruler and thickness gauges (refer to the tolerance).

Cracks on the pressure plate

Grooves on the pressure plate friction surface

Vehicle behavior ●● Very fast wear of the facings ●● Clutch slippage Reasons ●● High thermal stresses induced by repeated over heating clutch operations. ●● The cracks make the pressure plate friction surface very abrasive and therefore, accelerate the facings wear. Ɂ Ɂ Advice   To secure the life of the clutch, always start the vehicle in first gear.  Always replace the 3 parts of the clutch kit.  Always use the crawler gear (when available) to make the vehicle start in very difficult conditions.

Reasons ●● The facings are totally worn out. ●● The facings are destroyed by centrifugation or by overheating. Attention Ɂ Ɂ Stop he vehicle as soon as the clutch slippage occurs. Advice   Check periodically the wear of the clutch facings as suggested by the manufacturer (indicators, measures…).  Check the flywheel's condition (re-machine or replace it if necessary).

Advice   Always replace the 3 parts of the clutch kit.

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