Non-releasing clutch: the reason, and ? re cracks in flywheel

["Mark Battley" <m.battley@domain.elided>]

Firstly, thanks to everyone who gave advice about removing the clutch: votes
were fairly evenly split between motor + box, and box alone. And one vote of
engine only. In my case I removed the box only, which wasn't as
tricky/cramped as on some other cars I've done the same job on. At least it
is a relatively light box. Worst bit was getting the starter motor bolts
out: on a RHD drive car you have the steering box as well as the carbs in
the way. Usual DPO factors, ordinary rather than shoulder bolt on the
starter, one bellhousing bolt missing on the other side, and welded exhaust
so I had to drop the exhaust at the head.

And the answer is: one of the springs from the centre of the DRIVEN plate
had "escaped" (one of the metal tabs that locate it had broken off, seems to
have cracked from the corners of the rectangular hole out to the outer
circumference of the plate centre) and was wandering around inside the
pressure plate along with the remains of the tab. I've got no idea why or
how....

The driven plate was fairly well worn, but still had some life left. The
pressure plate seems okay, but I'll fit a new one to be sure. There was no
damage to friction surfaces on the pressure plate or flywheel.

However, the friction surface of the flywheel is covered in lots of fine
radial cracks. I've read somewhere that this is common for these, but:

    1. Does it matter?  if so..

    2. What is the solution: typically how deep are they: is it enough to
just get the surface lightly machined? (along with the clutch mounting
surface of course to keep the relative distance correct)

The old clutch worked fine, although had very slight judder on a hill, which
may also have been due to  the stuffed gearbox mount and giubo (both of
which will of course be replaced).

Thanks,

Mark Battley
Auckland, New Zealand.

1974 Alfa Romeo 2000 GT Veloce

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