Unlike brake shoes there isn't really an official Triumph figure for clutch
driven plate (disk) thickness as the 3 locking bolts on the arms of the clutch
cover allow for adjustment. A brand new disk has a thickness of about 8mm. When
fitted to the flywheel correctly the arms should be parallel to the flywheel and
the release lever plate should be 46.5mm above the flywheel. This is important
for correct action of the clutch.
Look at the disk very carefully, look for oil contamination of the surface,
burning and cracking of the lining. The damping springs should also be tight. If
it's rivited (the originals were) you need the lining to be at least 4mm above.
New linings are often much thicker (they are now asbestos free) and as a result
the arms needs adjusting.
The disk itself is unique to Amphicar, the lining is a standard size but the
centre piece is very special, don't loose it ! The clutch is a bit of a weak
part, Amphicar is much heavier than the Triumph and the design was at it's
limit. Triumph used a completely different clutch design on the later 1300cc and
larger engine cars - which can't easilly be fitted to Amphicar.
It's one of those parts where if it's a real pain if it doesn't work first
time - probably safest is to get a rebuilt disk from Hugh.
When everything is apart check for crank end float on the engine, a common
Triumph problem, dimensions in the book, and also check for leakage from that
oil seal on the end of the mainshaft into the transmission, a special Amphicar
Finally, be careful that the little bronze bush doesn't fall out of the back
(flywheel) end of the crankshaft.