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Big saloon gearbox strip-down - clutch release fork


Mjit

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I take it the theory is you snip the locking wire, unscrew the pin bolt, then the clutch leave cross shaft slided out of the gearbox, with the clutch release fork dropping in to the bell housing as it goes?  And not that you snip the locking wire to discover the pin bolt has sheared at a point where it's still interfearing between the shaft and fork?

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You are correct about the theory. Practice quite often matches your experience though.

You’ll find a fair bit about this on the forums as it afflicts saloons, TRs and manual Stags.

Can’t remember if there is enough swing available to be able to drill through from behind and punch the remains out.

Sacrificing the shaft and cutting it into sections is the quick and dirty method.

Nick

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The best you can hope for is persistant wiggling and tapping and the stub drops out.

I usually give up after an hour or so.

Assess whether the shaft or fork is the more worn and cut the worst one with a grinder.

if you cut the shaft you can the drill the hole in back of fork and punch stub out. If you cut fork then you can rotatbshaft 180 degrees and drill hole in situ and save shaft.

fit new cross shaft bushes whilst you are in there.

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For the TR clutch fork it is always recommended to fit an extra bolt/roll pin etc at 90 degrees to the taper pin in the middle of the fork body.

On my 4A I purchased a fork from the TRShop back in the 2000's that had a snu fitting hole up inside the for to receive the end of the taper pin. 

I have not seen a new one like it since.  The taper pin lasts forever as it is in double shear.

On my TR4 the internal hole (clearance drill size for the taper pin thread) was too big for the end of the of the taper pin  so I bushed the hole and turned the end of the taper pin down

into a parallel nose that fitted the bush nicely - this put the pin in double shear.

But it really is easier to fit the extra bolt/roll pin.

 

Roger

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35 minutes ago, thescrapman said:

 

fit new cross shaft bushes whilst you are in there.

I discovered James Paddocks (probably others) sell a double width bush. Handy as my sprint box was suffering, the case was being eaten by the shaft, but the double width bush has saved it. 

In the depths of my iffy memory, somebody posted about teh need for the tapered pin to be a good fit on the fork and the shaft, and some are not, leading to quick failure.  It was quite in-depth, but not sure which forum it was.

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Hi Clive,

Indeed. Any slack in the taper fit will convert the shear force into a tensile force = snap.

The pins are more than strong enough when in shear.  The structure is a single shear mechanism - supported only at the bottom of the pin.

If it was in double shear then any slack becomes less important.

As the pins, the fork and the shaft are all made in different countries then it is not surprising they are slack (slack = measured by foot/pedal pressure not by hand)

 

Roger

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