Steve Nabors wrote:
>My clutch has been making noise for some time now when the pedal is
>depressed. I figure the throw out bearing is going bad. Outside of the
>noise the clutch is working fine. Its been doing this for about 2 months
>so I went ahead and got most all the parts I think I'll need. I've noticed
>fresh oil in the driveway(a novel thought) where I crank up and put the
>clutch in every morning. Over the past week the sqeaking sound turned to
>screaching sound. Then it happened, you crank it up one morning and the
>car won't go into gear with all the screaching as before. I figured this
>might be due to one of two things:
>
>1.Clutch drive plate has oil on it from a bad rear main seal or bad tranny
>seal.
>2.The bad throw out bearing(TOB) has caused enough wear on the fork pins
>to loose enough effective movement.
>Question: Can a bad TOB cause the car not to go into gear? Could the
>bearings be so far gone as to collapse enough to create effective lost
>movement of the fork?
Steve, last October I finally changed my clutch after driving on it for
much, much longer than I should have. I had a bad TOB, and I was
experiencing similar screaching noises. It held together for quite some
time. I first noticed some "typical" TOB noise in February of last year,
then the screaching began in May and I didn't tear into it until October.
What I discovered, and what I'm guessing you'll also discover is that not
only did I have a bad TOB, but two fingers in the diaphragm spring were
broken off. The TOB itself was demolished. Nothing but a shell (loose)
and some steel balls. The TOB had separated, the inner race still stuck to
the collar. Everything was still basically where it was s'posed to be when
I first looked inside the bellhousing, but it all fell apart and steel
balls went everywhere as soon as I touched it!
I suspect that you've lost the motion required from the following
worn/broken parts: ground-down fork pins, enlarged (by friction and wear)
channel on the TOB collar (where the fork pins ride), a trashed TOB,
possibly broken diaphragm spring on pressure plate, and possibly a broken
"taper pin."
>I checked the movement at the pinned connection of the slave pushrod to
>the pivot bar of the fork. There are three holes there and mine was pinned
>to the innermost(radially) hole. It appeared to be at an awkward
>position(cocked) and the outermost looked better for making the pushrod
>more linear to the slave cylinder.
>
>Question:Does anyone know which hole is correct?
The CENTER hole is the correct hole, and should work properly if everything
else in the bellhousing is in good shape.
>The linear movement of the slave cylinder pushrod 'looked good enough' at
>about 1.25~1.5 inches upon pushing in the clutch pedal.
Lateral movement should be around 5/8 of an inch. Don't know how you could
be getting so much movement. Is that an "eyeball" figure or did you
measure it with a ruler?
>At this point I'm about to dive into the clutch as I know/assume I have to
>replace the throw out bearing(TOB) anyway. I plan to replace the pressure
>plate, friction disk, TOB, sleeve, 2 fork pins , 2 fork pivot bar bushings
>and fork lock screw. On the engine I plan to replace the rear main seal
>and both seals on the tranny.
>
>Question:Does anyone have any suggestions or pointers on things to look
>out for(besides the car slipping off the jackstand ;-)?
Check out British Parts Northwest... they sell a heavy-duty clutch that is
supposedly identical to TRF's "Magic Clutch." It is supplied with a Toyota
TOB already pressed onto a new collar, and a SACHS pressure plate. The
price is about $200 for the kit. This is what I did last October, and so
far I'm still very pleased. I only got about 25,000 miles on this last
OEM-type (Laycock) clutch, and in that 25,000 I changed the TOB once! That
is, the disintegrated TOB only had about 17,000 miles on it! Needless to
say, the OEM TOB's don't seem adequate for the job. Although, as I
understand it, this may be the result of my "installation technique"... the
TOB's apparently are succeptible to damage upon installation onto the
collar... this could have been my problem. The clutch itself was shot,
too, in my case.
Also, there are some mods we can talk about to prevent further problems
with the "taper pin". This is the locking pin that secures the fork to the
cross-shaft. I had a new pin fabricated at a local machine shop, which
involved slight modification of the cross-shaft and the fork as well. The
guy here charged me $35. I should not EVER have to change that pin again
or even worry about it failing. If you'd like details let me know and I'll
give you the necessary info directly.
Good luck!
Pete Chadwell
1973 TR6
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