Rainer Wallnig wrote:
> At 09:02 17.02.99 +0100, you wrote:
> >
> >Item Subject: cc:Mail Text
> >
> > Hello Triumph Fans,
> >
> > While changing the clutch in my 1963 TR4, I've found that the tapered
> > pin, which holds the clutch release arm onto the spindle, has broken
> > in half. I see that Moss recommend changing this to a hardened type of
> > pin, so I've ordered a new one. Unfortunately, half the pin is still
> > stuck in the hole! Access is very difficult, and even after several
> > days of WD40 and gentle knocking, it just won't budge.
> >
> > Does anyone have any ideas of how to get it out? The best idea I have
> > so far is to drill a small hold in the arm on the other side, and try
> > to tap it out with a bluntened nail.
> >
> > Gerard Winn
> > 1963 TR4
> >
> Hello Gerard,
>
> your method will be the best. But do not install the hardened pin. It will
> break again and the whole trouble starts from the beginnig. I have
> exercised it all! The best method is to weld the arm to the spindle. If you
> will ever have to remove it, you must cut it off and weld it back.
> Not very elegant but it works!
>
> Good luck, Rainer Wallnig, TR4 63
Gerard,
This comes up every so often on the list. I recommended our technique some
months ago
to several folks in your situation, and I believe that they have had excellent
results.
The fundamental engineering problem with the clutch fork is simply this:
The pin is tapered.
The cross-shaft has a tapered hole to accept the tapered pin.
The partially threaded bore in the fork IS NOT TAPERED!!!
What this means is that contact is made on only one side of the fork pin. (the
side
nearest the threaded portion just below the head) All the force is
concentrated at
that spot and the pin will ALWAYS break at this spot - never anywhere else.
The best,
albeit not so easy, solution is to ream the hole in the cross-shaft to the same
diameter as the bore in the deepest part of the fork. Then fabricate a new
pin, one
with a straight shank of corresponding diameter + .001" for an interference fit
that
will tightly engage both sides of the fork. No modifications are made to the
fork,
but now the shear force is divided equally between the top and bottom of the
new pin,
which is also slightly larger in diameter than the original tapered pin.
The real benefit comes from the fact that the topmost portion of the pin extends
directly up into the right-hand finger of the fork, thus there is no chance of
overstressing or cracking the base of the fork around the shaft. I know it is
not
exactly a do-it-yourself prospect to make such a set up, but just about any
machine
shop can make a pin for you fairly easily.
Good luck!
Regards,
Brian Schlorff '61 TR-4 '64 TR-4 '72 TR-6 '79 Spit
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