Randall,
Thanks for feedback. The TR250-6 did not come with the threaded fork lever
nor spring -- it is not adjustable. One of the TR experts (might have been
N. Riedel) wrote that he thought that the bearing on the TR250-6 was meant
to stay in contact with the driven plate, thus continuing to spin, but he
wasn't sure. He conjectured that the threaded fork lever with spring would
definitely pull the bearing back so it was out of contact and would be at
rest during driving. Since the Koyo is stiffer, he thought that there was
not enough pressure to ensure that the Koyo also spun, yet because it was in
contact, wear would ensue. If he is right, it might also explain why the
bearing on the 6-cylinder cars seem to go bad sooner than on the earlier
cars. If the bearing is in contact with the driven plate, and hence always
spinning, then it had better be perfectly coaxial with the driven plate,
otherwise you can imagine that the rotation of the bearing could become
slightly eccentric and that can't be good. This may be why it seems to be a
really big deal on the 6-cylinder cars to line up the gearbox perfectly with
those dowl pins -- to ensure that the bearing and the driven plate are
coaxial.
I ordered the clutch shaft "kit" from TRF, RFK1249, which comes with the
cross shaft, shaft bushes, pin, and lever. It is listed as the part for
T46, so is for 4A-6. I looked up the part number you gave, it lists it as
applying T23. Part SUAUC2256 is also listed as the fork for T24, and 138247
is the part for T46. So, those with a TR4A should probably keep their old
adjustable fork if they order the TRF kit. I think that often TRF tends to
lump the 4A clutch parts in with the 250 & 6; they don't realize that there
is a difference. The best example is the clutch itself. All of the parts
suppliers list the same clutch for 4A-6, but the 4A actually had a different
B&B clutch that had less spring pressure. Only Moss UK sells the correct 4A
clutch these days, and it does make a difference in pedal pressure and
probably longevity of the T/O bearing.
Well, I'll give the Koyo a go and hope it all works well. Would hate to
have to pull that gearbox again...
Thanks
Chris
----- Original Message -----
From: "Randall" <tr3driver@comcast.net>
To: <triumphs@autox.team.net>
Sent: Monday, June 19, 2006 6:23 PM
Subject: RE: [TR] Koyo clutch release bearing
> > Note
> > that my 4A has the slave cylinder arrangement of the 4 and earlier
models,
> > meaning that there is a spring that pulls the release bearing back out
of
> > contact with the clutch pressure plate and the operating fork lever is
> > threaded and can be adjusted.
>
> In that case, Chris, there should be no concern over the stiff bearing
> causing problems. In fact, converting to that arrangement is one of the
> acknowledged fixes for the problem (on later cars). Just keep it properly
> adjusted (so there is some free play at the slave) as the clutch wears.
>
> > The later slaves/forks on TR250-6 don't have
> > that (and neither do the replacements from TRF, even for 4A).
>
> Interesting. At one time, the adjustable forks were NLA, but Moss has
them
> listed now. Perhaps the Glovebox Companion listed a substitute and was
not
> updated when they became available again ? What was the P/N ? (Should be
> 57194, I think.)
>
> Randall
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