Non releasing 105 clutch

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

The clutch on my 74 2000 GT Veloce has decided that it doesn't want to
release, at least that's what it feels like.

Story so far: I was giving the car a mild Italian tune up on a twisty bit of
road near home, went to change from 3rd to 4th, wouldn't go into 4th... or
any other gear. Coasted to a stop, still wouldn't engage any gear with
engine running, would with engine stopped. After trying a few gears it
suddenly went into gear with a slight graunch (typical of gear engagement
with overworked syncros), and an odd scraping/rattling(?) noise. And then
behaved perfectly for the rest of the drive home... 

Went to go out again a hour later, same again, wouldn't engage any gear.
Seems like a stuck clutch: can feel the syncros trying to do their stuff, if
I push a bit harder get the expected graunch. Hydraulics are working,
release lever is moving far enough, clutch weight and travel feel normal.
Won't release even without motor running. I've had as much of a peer into
the bellhousing as is possible, can't see anything obvious. Tried starting
the car in gear, just moves the car, although did a hear some of the odd
scraping/rattling(?) noise again.

Any guesses? Anything else I should check before pulling it apart?

The odd thing is that it fixed itself for a while. Maybe it just wanted to
go home!

My best guess so far is that some of the friction material has come off the
plate and is jamming everything up. Which would fit with it curing itself
briefly. If it was the release bearing or the pressure plate diaphragm the
pedal pressure should feel wrong (??), and I can't see how it would fix
itself.

Whatever, can't see how I can avoid pulling it apart. I've had gearboxes and
clutches out of a variety of other cars before, but not one of these. Is it
easier/quicker to drop the box out by itself, or pull the motor/box out the
top together? 

Thanks,

Mark Battley
Auckland, New Zealand.

1974 Alfa Romeo 2000 GT Veloce

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