Nelson---"Questions for the List..." You have made some good
observations. At least it lines up with what I found! :^ )
This would be a good time for all those tuned in who have never had a
problem in this area to go to the next message, as my reply will by
necessity be long.
Nelson, the "sticking clutch" is probably separate from the squeal, I
believe. Reluctance for the clutch to engage sounds like a problem of
frictional resistance. Good sliding surfaces and appropriate grease will
go a long way to letting the clutch out smoothly.
After giving up on the original style T/O bearing, due to it's too short
of a life, I went to the KOYO, by Toyota. It is as you described. Stout,
larger, and by definition should take more force to get it spinning.
Mine was in operation for about 2,000 miles before the dreaded "squeal"
showed up one week ago. It sounded so much like a standard bearing just
before these failed, that I was certain the KOYO was also letting me
know that it, too, was about to give up. Last Wednesday I called TRF and
talked to Dave, telling him that this Magic bearing doesn't seem to be
the answer either. We exchanged ideas, and not surprisingly including
some in your post today! He sent me a new KOYO, but I knew that there
had to be something else going on.
I took the clutch out again last Friday, and found the bearing to be OK.
I tested it in my drill press, using a force of 300lb. It WAS its
primary engagement with the diaphragm fingers that brought on the
squeal, disappearing just before the force that disengages the clutch.
Its sleeve and front cover was smooth underneath the MOLYKOTE, as was
the splined area and clutch shaft at the case bearings.
My clutch was, and is, set up to NOT ride on the bearing when it is
engaged. I had long ago removed the SC spring, and added an exact return
spring to the lever arm to guarantee no 'drag' was present on the T/O.
Your idea to let it ride full-time is certainly worth considering, as it
would remove the wear and possible squeal of initial contact with the
diaphragm fingers. My reluctance here is not knowing if the bearing is
up to the task of constantly spinning. Dave said he would ask * to see
if this was part of the Toyota design to allow it to do so.
I noticed in your photo that the SACHS cover has flat fingers, different
than the "blue dot" Borg and Beck that has the compound angled fingers.
I was hoping the larger surface area that the SACHS has would start the
bearing spinning, before any slip-squeal would take place.
This means that my idea of the older B&B clutch just installed (with
flat fingers) is also going to eventually squeal again.
On the need to "adjust" the TR4 style pushrod when wear occurs inside
the clutch housing...it shouldn't be necessary. The SC piston will
'reset' according to the return action of the clutch. I do agree that
the clutch will tolerate no lost motion, and every effort must be made
so the SC piston is not forced too far back into its bore when the
clutch is at rest. In otherwords, an outside spring force must be exact.
(I use a turnbuckle to dial in)
As always, I enjoy this type of exchange, and it benefits us all when we
can gang up on a problem. I'll let you know the answer to your no. 2 *
when I find out something here.
Dick Taylor
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