Valeoscope Commercial Vehicles Clutch 2020

Diagnosis Hard gear shifting

10. Diaphragm radial breakage

11. Dust or pieces of the facing between the cover and the pressure plate

12. Breakage of the fork contact area

13. Judder caused by grease

Parts inspection Wear or breakage on the fork contact areas. Vehicle behavior Generally, such issues can affect the clutch operation in: ●● Hard declutching ●● Unsmooth clutch engagement ●● Hard shifting

Parts inspection There is grease on the clutch facings Vehicle behaviour ●● It is impossible or difficult to shift gears ●● Slippage of clutch in hot conditions ●● Judder Reasons ●● Oil leakage from the gearbox or from the engine ●● Grease leakage from the pilot bearing ●● Excess of grease on the clutch disc splines or on release bearing sleeve

Parts inspection Dust or pieces of facing between cover, diaphragm and pressure plate. Vehicle behavior ●● Impossible or difficult to shift gears ●● Clutch slippage Reasons ●● Severe usage of clutch ●● Wrong conditions or wrong adjustments of the clutch linkage ●● Mistake in using the gearbox Diagnosis ò ò Facings destroyed because of overheating ò ò Centrifugation of facings ò ò Pieces of facings are spread inside the cover assembly

Radial breakage of diaphragm

Parts inspection Radial breakage of diaphragm Vehicle behavior ●● Impossible or difficult to shift gears ●● Slippage of clutch Reasons ●● Wrong adjustments of the clutch linkage ●● Clutch linkage out of specifications Diagnosis ò ò Such issues often happen due to the excess of bearing travel. ò ò The diaphragm stress has exceeded its mechanical resistance. Attention Ɂ Ɂ Check conformity and function of the clutch linkage parts. Ɂ Ɂ Follow the manufacturer’s recommendations concerning their adjustment. Advice   Replace the 3 parts of the clutch kit.  Check the bearing travel and the condition of the actuator  Be aware of diaphragm spring quality and characteristics of non-original products.

Breakage of fork contact area

Reasons Because the fork contact is not symmetrical, the consequences can be: ●● Insufficient bearing travel ●● Increased slipping time (reduced release bearing speed during engagement) ●● Rough vehicle startup (shocks, shuffle) Diagnosis ò ò Insufficient greasing on fork contact areas. ò ò Wrong condition of the fork or of its pivot system. ò ò Intensive use of the clutch due to the vehicle usage type generating fast wear at fork contact areas. Attention Ɂ Ɂ To insure good function and long life of your clutch, it is necessary to apply appropriate grease at the release bearing/fork contact areas. Advice   Check and refit the clutch linkage (fork, axis, and pivot).  Replace the fork when its contact areas are damaged.  Grease the fork contact areas when the fork has no roller.  If the fork has rollers, make sure that they are not jammed; greasing the fork contact is not necessary.

Grease on the facing

Diagnosis The diagnosis is quite difficult and can sometimes be done through the clutch housing hole. ò ò Using a stroboscopic lamp, it is possible to see the displacement of the disc. ò ò Facing adhesion on friction surfaces (flywheel, pressure plate) prevents the clutch disc from moving along the splines. ò ò Facing friction coefficient has dropped and become unstable. It generates: • Unsmooth vehicle start-up (vehicle shuffles during clutch engagement in both forward and in backward). • Insufficient clutch torque capacity (mainly in hot conditions, full engine torque) Attention Ɂ Ɂ A clutch disc with facing contaminated by grease cannot be used again and must be replaced.

Dust or pieces of facing

Attention Ɂ Ɂ It is impossible to re-use a cover assembly covered with facing dust. It cannot be completely cleaned and has to be replaced. Advice   Check the conditions and the adjustments of the clutch linkage.  Replace 3 pieces clutch kit and clean the clutch housing.

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