clutch cunundrum

[dazzer]

There I was minding my own business rebuilding the rally 2000 for the Rally of the tests (2 weeks!) until I bled the clutch... pop and the clutch fork lever went limp and the piston popped out of the slave... For the life of me I have no idea why its decided to do this. Has anyone experienced this before?

Until I drop the box out again I can only speculate. I believe the fork slipper pads have travelled too far and popped out of the release bearing carrier. But why I have no idea.

This is a completely rebuilt J type (used it previously) mated to a early 2000 MK1 narrow head engine. Everything is rebuilt and pristine. New slipper pads, carrier, release bearing, AP clutch etc. A set up I've used umpteen times before.

Questions: Are all the early MK1 cranks the same (2000). Are all the flywheels the same thickness?

The only thing I did different was fit a land rover slave rather than the generic. slave fitted gearbox side of bracket (not as Haynes) centre hole, but even so shouldn't break anything. This was first push of the pedal. No resistance at all in the in the lever fork arm now, just flops about can move it backwards and forwards in both directions as far as it will go.

Ideas?

[TedTaylor]

Thank goodness there are more than two of us with clutch problems ....... I can't bleed mine from Woodie the Mk2

Only engine change for the Mk1 2000 was the introduction of the later type in about 1968? which carried over to the Mk 2s (with the square casting for the engine mount).  Until then as far as I am aware there were no changes.

Is the revised (Landie) slave of the same bore as the original Triumph one?  If it is a smaller the and piston will travel further.
Sounds like your slave mounting is correct.

MUT

[piman]

Hello Dazzer,

possibly the taper bolt in the shaft has sheared, sometimes this happens and the shaft only rotates a small amount before it grips again but that doesn't have to be the case? I think it's unlikely the fork has come out of engagement from the thrust bearing carrier as for this to hasppen the clutch would have to be depressed a very long way, impossible in my view?

Alec

[Nick Jones]

I think your diagnosis is probably correct.  Not sure why though.

I do know that with the mk1 engine there are various possibilities of long back and short back cranks and flywheels that have to be used in the right combination to put the clutch fingers in the right place.  There may also be different length release bearing carriers.

I think the LR slave cylinder is probably a red herring unless it's really small bore causing a long stroke.....

I suppose it's possible that the famous taper bolt has sheared......

Bad news having to drop the box again whatever - especially against a deadline!

Nick

[Radders]

Possible broken pin in the cross shaft?

[Pete Lewis]

if the fork had dislocated from the carrier i guess the x shaft would slide left/right as the carrier is about all that locates it.
roll pin or dowel bolt seems favourite . but the dowel bolts a always feindishly tight and pretty hardend things .
if the roll pin had failed i reckon the lever would show signs of falling off. its shaft

cant see any size of slave variation giving you what youve found ., could give operational hic ups but not all that lost /loose lever travel

Pete

[thescrapman]

If it is the taper bolt snapped (did you fit a new one?? Bad boy if you didn't!!!) and you manage to get the remains out so you can withdraw the cross shaft, then drill a hole in the bottom of the cross shaft so if it happens again you can knock the remains out. You won't be lucky twice.

Other thought is that there is a different length carrier for the release bearing or you didn't engage the fingers in the right place. Or perhaps the slipper pads were missing?

Cheers

[dazzer]

Eureka! Just crawled underneath the car for a closer look. Its the lever thats parted company with the cross shaft. Its just spinning round the weld must have parted company. Bit fiddly to get at but I reckon I know a welder that can do that in situ. Ive never seen that before has anyone else? Just need to know the correct position now. Is it just straight down? Any images gratefully received Darren

[Nick Jones]

Seen it happen on a Sprint before (mine!), but I think the arm was "converted" from a big saloon one by AN Other and the removable tunnel cover made sorting it rather easier.  It was benevolent enough to fail in the driveway too......

Not sure about the position.  If you have a close look at the broken weld you'll probably be able to see where it was.

Be a bit careful about the amount of heat as some of the bush materials used (though probably not the OE ones) might not survive a really thorough roasting.  They are at leat a tight fit in a really big heat sink!

Nick

[piman]

Hello Darren,

that's a new one, at least for me. Do you have an angle grinder with a cutting disc? If you can re-align the arm and shaft using the fracture and match the two parts then grind a line across the arm and shaft end. To do a good weld will need the arm to be removed and countersunk and the shaft end shamfered to ensure decent penetration. The line will then give correct orientation. Simply running a weld around the shaft and arm as is is not ideal.

Alec

[dazzer]

Thanks All for the ideas and advice. Nick mentioned his Sprint incident and it does appear quite frequently on Sprint forums with all sorts of welding resolves.

Alec. I'm going to get it welded in situ and to help access I may cut an access panel into the tunnel to make the job easier. I'll get Ian Jemison to weld it who has done all the other welding on the car sills, alloy wheels, new diff pin mounts, exhausts etc. Always uses gas and even welds magnesium wheels. So if anyone can do it Ian can.

Cheers
Darren

[piman]

Hello Darren,

Yes I assumed you were, the access panel is a good idea. He'll need a large nozzle, braze or weld?

Alec

[dazzer]

Hi All

Just for your info. Check any 'new' gearbox cross shaft and levers if fitting as the problem wasn't a weak weld but no weld!

All it had was two light spots ready for welding but then someone had obviously gone for a tea break or something and it never got welded.

I didn't notice this when fitting the box but then why would I check to see if it had been welded.

I may just be unlucky or there maybe more out there.

Cheers
Darren

[Nick Jones]

Oh.....!  That explains it....... 😲

Nick

[dazzer]

As a sub note. The cross shaft and lever Ive now been told was a new Moss item. Info has been passed on and inventory checked.

Cheers Darren

[Pete Lewis]

just doing a refurb of my mk2 gearbox and following this thread checking  the taper dowel in the withdrawl has failed , unscrewed the base but the broken taper is seriuosly stuck in the shaft and wont allow me to withdraw the shaft .
so angle grind the shaft into two to extricate the blasted thing seems the only option, then on bench  theres access to see down the fork tapping to see whats left inside or not

any good ideas welcome

Pete

[thescrapman]

Pete

You can try lots of tapping and wiggling to see if the remains of the taper will eventually move, not overly successful for me, worked once,, but worth 10 mins of you time. Or perhaps a bit of heat?

Then get the grinder out.

Make sure you fit new cross shaft bearings whilst you are about it. just knock old ones inwards and leave them there. Chris Witor sells wider ones as well. Even better.

Cheers

Colin

[Richard B]

Drill into the fork with a 1/8" drill from the top of the Y.

Then use a drift to remove whats left of the pin.

[Pete Lewis]

Im not normally stuck more into giving solutions,  senior moments prevail
will try both ideas if Hic  hic chritmas can wait
pete

[Pete Lewis]

Well the lever had the punch hole already drilled  took a lot of aligning to get to the backend of the dowel but , its out
the shaft is not that clever at  the break point
but will access with new uprated dowel and lap in with some grinding paste , see what sort of fit I can get ,  it may be a new shaft is on the cards to make  a reliable fix

pete

[esxefi]

can't you drill it out and retap to a larger size?

I did this with my old sprint box,drilled and tapped out to m12 and fitted a decent lock wired allen bolt  right into the fork,never gave any issues for 20+yrs with an uprated ap cover n'all.

[piman]

Hello Esxefi,

I have seen other people saying they drill an extra hole and use a nut and bolt. However it can never be as good as a properly fitted taper bolt. If you ream a hole in the shaft and the fork and use an accurate machined bolt it is not as rigid. There will always be a slight movement which you should not have with the original taper bolt.
I acknowedge that your modification worked but it is not sound engineering.

Alec

[Pete Lewis]

http://www.buckeyetriumphs.org/technical/clutch/ClutchShaft/ClutchShaft.htm

The buckeye triumphs site gives a whole plethera of trials and tribulations into this tapered dowel failures
the shaft hole is definitley tapered, I will get  a new hd dowel from RB and check its fit before I jump to a new shaft but its not overly £££s

So replace to be sure is not the end of the world, I dont want to take the box off again
peter

[Richard B]

Definitely a taper, If the pin is under size it can bottom out in the fork without gripping correctly.

I heard (somewhere about putting a parallel pin on the other side of the fork (horizontally not vertically like the taper) The two pins prevent the fork for twisting on the shaft and help stop the taper from snapping.

[piman]

Hello pete,

to get a good fit requires the taper in the shaft and the fork to be reamed together. Somewhere in the past I seemed to remember Chris Witor selling the right tool?  It's also essential to ensure the taper bolt's thread does not bottom on the fork, which could happen if the reaming is too enthusiastic.

Alec