Valeoscope Commercial Vehicles Clutch 2020

Diagnosis Hard gear shifting

4. Deformed straps

5. Worn facing with cavities and shiny surfaces

Parts inspection ●● The facing is shiny on most parts of the friction surface. ●● There are some cavities. ●● The facing rivets are not drilled. Vehicle behavior Wrong clutch release mainly in warm conditions, with: ●● Gearbox noise during reverse gear engagement (whatever the duration of clutch disengagement is). ●● Hard gear shifting while driving. ●● The vehicle tending to move, gear engaged in declutch position.

Deformed straps

Parts inspection Straps are deformed. Vehicle behavior It is impossible or difficult to shift gear. Reasons ●● Drop of the cover assembly before fitting (during transportation or handling). ●● Deformation occurred during cover assembly bolting operation (use of a lever between cover and straps or between pressure plate and straps to prevent rotation of the cover assembly). Diagnosis ò ò Wrong pressure plate lift  the clutch disc is not released completely. Attention Ɂ Ɂ Handle the cover assembly carefully; a shock on cover side can damage the straps. Advice   Check the straps before cover assembly mounting. The straps must be in contact with each other along with their total length and they must not show any bending mark.

Suction phenomenon

Reasons ●● The clutch disc cannot slide on the input shaft splines and stick to flywheel. Despite a good pressure plate lift, the input shaft is always in rotation. ●● Warm air is confined. Inside the cavities of facings (rivet holes, facing cavities) which create a suction effect with the flywheel. ●● This phenomenon happens more frequently on large size clutch discs (380 to 430 mm) in which the usage conditions are not severe (high frequency of gear change under low energy dissipation). Diagnosis ò ò It can be checked through the holes of clutch housing by using a stroboscopic lamp (if the clutch layout is compatible). Attention Ɂ Ɂ This issue is rather special when the clutch is a low quality reworked product (rivet type, facing material; non-grooved facing with steel back).

Clutch disc with grooved facings

Drilled rivet

Worn facing with cavities and shiny surface on outer diameter

Advice   To avoid it, use only Valeo productswhich have been designed for the correct adaptation.

Valeo Solution

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