The role of the release bearing

The release bearing transmits the movement of the fork to compress the diaphragm.





The components of the release bearing:
· Metal back plate 1
· Guide sleeve 2 made of (polyamide 6.6.) It has splines to control any misalignment of the clutch fork fingers.
· Roller bearing: the internal collar 3 is in contact with the diaphragm fingers. The external bearing carrier 4 is held on the sleeve by the retaining spring 5.

Various types of release bearings are used on vehicles:
· Push type: press down on the diaphragm fingers to release the pressure of the spring this is the most common type.
· Pull type: This is of the self centering and pre loaded type. Pulls on the diaphragm fingers to release the pressure on the springs. Can be fixed to the diaphragm or clipable/removable during assembly.
· Self centering: the bearing floats on the sleeve so that the bearing can move to line up with the clutch cover and diaphragm fingers resulting in greater smoothness during operation and greater life.

Problems caused by defective release bearings:
· Pedal is hard to depress - bearing may have worn the tips of the diaphragm fingers resulting in too low preload.
· Stiffness at point - damage to sleeve of bearing or travel, gears - bearing guide is worn fork guide is worn or bent.
· Noisy clutch and pedal - locating lug on bearing can be slack, worn or broken.
· Harsh whistling noise can be slack - siezed or damaged bearing, or overheated bearing