If the clutch friction plate is damaged in any way, or if the
friction material is worn to the rivets, fouled with grease or oil,
or glazed, it must be renewed as a matter of course. If it appears
to be in good condition measure the thickness of the friction
material at several points; if the plate is worn to 4.5 mm (0.1772
in) or less at any point, it must be renewed.
Check carefully the condition of the friction plate centre
splines and check for signs of cracking or splitting around the
centre; if any damage is found the plate must be renewed.
Check the friction and pressure plates for distortion and the
spring pressure of the diaphragm spring; renew any component that is
found to be damaged, worn or otherwise faulty.
If the clutch action has become sudden, with grabbing or
snatching in evidence, first check the release mechanism (see
Section 6). If this is in good condition check closely the gearbox
input shaft and friction plate centre splines; renew either
component if excessive wear is found. Lastly check the preload of
the input shaft. See Chapter 3 - Gearbox.
If the clutch has been slipping and the plate friction material
is found to be in good condition, the clutch cover plate should be
checked very carefully and renewed.
If oil has found its way into the clutch housing, thoroughly
degrease ail clutch components and wash all traces of oil off the
crankcase and gearbox castings. Check the seals at the output shaft
rear end and the gearbox input shaft front and rear. Check carefully
that the housing has not been rubbing on the output shaft seal,
renewing the seal if traces of this are found.
Note that the clutch housing retaining nut is of the
self-locking type and must be renewed whenever it is disturbed; also
the housing O-ring.
If severe damage to clutch components or excessive wear of the
splines is found, check that the locating dowels are fitted to align
correctly the engine, bell housing and gearbox castings. There are
two large locating dowels set in each of the bell housing front and
rear faces; always ensure that these are refitted whenever the bell
housing joints are disturbed.