Dustin Howarth wrote:
>
> Here's what I found:
>
> -- evenly worn clutch disc that should be replaced, but doesn't appear to
> be damaged or disfunctional..
Is the friction material bonded or riveted to the plate?
Usually clutch plates work up to the point where the rivets start
contacting, but I suppose a bonded plate could get 'skinny' enough
to loose friction, though I doubt it. But it seems that your problem
was the clutch not releasing, where a worn friction plate would be
the opposite.
> -- throw-out bearing looks okay to me -- no uneven wear or broken pieces.
> There seems to be a good amount of bearing material (carbon?) left.
I've heard stories of these carbon TO bearings being in absolutly
horrible shape, yet still doing the job. ie, people doing clutch work
being very suprised at the poor condition of their clutch when they open
it up, when expecting just normal wear.
The
> swivel sockets connecting the bearing to the arm were somewhaat stiff..
>
> -- throw-out bearing arm (fork) had some slop at the connection to the
> transmission housing (maybe 1/4" to 3/8") -- seems like a lot of play..
Seems like alot to me too. IMO this could be the main culprit.
>
> -- pressure plate looks okay, no evidence of worn springs. There was a
> little bit of uneven wear on the throw-out bearing side of the pressure
> plate where the bearing meets the plate..
If your springs were worn, the clutch wouldn't hook up, whereas you
seemed to have the problem of not releasing. In my experience only
two things kill a pressure plate; one, the friction disk scoring the
plate badly, and two, broken springs. Weak springs can be a problem,
like in a '69 RoadRunner with a 400+ HP engine, but I doubt a Midget
generates the heat to weaken springs, and the HP to over come weak
springs. But I do agree to change the pressure plate (safe than sorry,
while it's convenient, etc.). Usually the TOB doesen't wear out it's
contact place on the pressure plate enough to be a problem, especially
since your TOB wasn't it such bad shape. But that wear is another small
factor in the problem.
> -- the hole in the clutch slave cylinder piston was a bit out of round
> where the throw-out bearing linkage connects, but doesn't seem too bad..
But another piece in the problem. Not totally bad, but it's really
starting to add up.
> Does that suggest anything to anyone?
I think your problem is the sum of all the little things is adding up
to one big problem. The problem is the TOB is not pushing the pressure
plate in far enough to fully release the friction disk. We can divide
the causes up like this; one, the linkage is sloppy enough to not move
fully enough, two, The TOB is worn enough to add to the problem (even
though it in itself is not worn out), three, the hydraulic system is
working- but could be better, four, simple age of transmission makes
the syncros a little more sensitive and potentially uncooperative.
My plan right now is to replace the
> disc, plate, and bearing, as well as the clutch slave cylinder piston, put
> it together, and hope it's okay. That seems disturbingly unscientific to
> me, but I can't see anything obviously wrong..
That's because no one part is bad, but they are all just worn enough
to conspire against you. I agree to replace the disk and plate on the
grounds that while you're in there you should do it, but not because I
think they contributed to the problem. The TOB should be replaced for
sure, and I would strongly recomend getting a regular ball (roller?)
TO bearing from MiniMania, rather than the carbon one. Most likely
either one will work, but as soon as the carbon one wears you could
end up in the same boat again, ie TOB not releasing even though it's
not worn out. The clutch slave is good to replace for both the above
reasons. There should be a reference in a shop manual as to how far
some linkage must move to release the pressure plate. But unfortunatly
these British manuals seem to be short on hard information like that.
Torque values can be just 'tighten', bushings are 'ream to fit', for
example.
I would really try to reduce all slop from the linkage, as I think
that's were you're really getting most of the problem from.
> Could the problem I described be in the hydraulic system?
Could be weak, like I said before, but it does seem to be working
somewhat inthat you could still get it to disengage most of the way.
I have both a '78 and a '71 Midget, I'll pessimistically check my manuals
for a reference to how far the TOB linkage must move to release the
pressure plate. If that is a dead end, I can measure one of my Midgets
linkage in a conveniant place of your choosing.
I assume your '73 Midget has the 1275 engine? I've forgotten what year
they switched to the 1500cc, either way I've got you covered.
-Aron-
"in a frenzy"
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