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Juddery Clutch


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Hi all

 

I am unsure of how to describe the issues on my clutch so best I can use is the term juddery, if even that word exists.

 

So I have (my mechanic) changed the two clutch cylinders (master and slave) and still an issue remains. The car, when pulling away, basically slams into motion when I engage the clutch, so rather than a smooth pull-away Mrs N's head gets thrown back and away we go! I will also say the pedal is not that smooth and also the bite (if you can call it that) is quite late - but main issue is the car leaping forward which is an issue in traffic.

 

Now winter is coming so am able to take off road for the work but what work I am unsure of, so reach out to you guys.

 

I would need to get a local mechanic to do this and this could be a wee challenge to find someone who knows these cars over here, unless of course its not such a huge thing to do.

 

I can post a video if necessary and must admit, a lot of the stuff I have read on clutches on the TR6 generally confuses me, ie Laycock this etc etc.

 

Appreciate any help on diagnosing this as I am concerned I order a whole new clutch, spend a fortune getting it fitted and it was not a necessary job,

 

Thanks

 

Rich

 

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Possibly the tapered pin on the throw out bearing fork is broken or Bent. A TR6 that I recently drove had the same symptoms. The fork was cracked, tapered pin was bent.

 

Graham

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Hi Rich,

I do not think it is the taper pin as that may cause issues engaging 1st or reverse it shouldn't normally cause judder.

You appear to have described ratchet clutch to a tee.

 

Basically you lift the clutch pedal, the release bearing carrier sticks on the front cover extension snout item #10 https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/clutch-transmission-drivetrain/gearboxes-components/gearbox-units-external-components-tr5-6.html.

With vibration etc the bearing jumps back to catch up with the retracting fork.

 

TR6's suffered this badly in the early days if the alignment bolts (item #17 2 off) were left out or put in the wrong place.

 

So you may be lucky and refit the two alignment bolts - keep GB insitu.

 

However if you are unlucky then the GB needs to come off.

 

Have a very critical look at the snout of the front cover extension - you may see witness marks where the bearing carrier gets stuck.

It could be worth checking the alignment of the snout to the splined GB input shaft - it should be concentric - my 4A GB was 0.015" vertically displaced.

 

Try this test.

With the engine switched off - press the clutch pedal and engage 1st gear. Now lift the clutch - did it feel as if the clutch felt normal.

If you have mis-alignment then this is normal because the release bearing is not being forced out of alignment.

With the engine rotating the release bearing gets thrown out of alignment and the carrier sticks.

 

What release bearing carrier do you have.

For a TR6, steel is normal (I have this on my 4A and it works perfectly)

Many people recommend the Phosphour bronze carrier - but it must be the harder dark yellow (old gold) in colour

The lighter coloured bronze carrier is for saloons and they have a different fork.

 

Good luck

 

Roger

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Hi Rich,

First place I would look would be gearbox alignment, Roger touched on this above, but if I may elaborate.

 

The six cylinder engine does not have locating dowels between the block and the gearbox, the four cyl engines do!

The alignment between the two units on the six cylinder is catered for by two 3/8 shouldered bolts, fitted at two o,clock and eight o,clock as you look at the engine.

 

Garages do not know this, and when a clutch is replaced, they often simply put any bolt anywhere, thus failing to effect accurate alignment of the gearbox and engine.

 

The cure, and the first thing you should check is this, strip out the car, seats, carpets, h frame and gearbox tunnel, you need to do all this for any repair. Loosen slightly all the gearbox to bell housing bolts, jus half a nut turn, and fully remove the nuts and bolts at two and eight o,clock,

Check if they have a 3/8 shouldered bolt, if yes , then you are looking at other faults, if no, then replace these bolts, tighten up the rest and after replacing the transmission tunnel, and drivers seat, go for a test drive.

 

Over the last few tears, in our local group, we have had this issue on three different TR 6's and this has cured all three, good luck.

 

John.

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Morning Roger!

 

Ratchet clutch, that is a new term for me! You are right, I do not have any issues on getting it into first or reverse, so maybe your prognosis is correct.

I was already thinking of buying a whole new clutch but guess that I should try your first idea and see how that goes. Then if that is a no-no then its GB out and onwards.

Would you say a decent mechanic, would understand what you write? I live in Denmark and the amount of true hands on experience on these cars seems limited, but if this is core mechanics maybe I am in luck. Now they closed the Esbjerg/Harwich the option to trailer over to UK is unfortunately a no-go.

 

Thanks again

 

Rich

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Hi John,

thanks for expanding on that subject - I had left the finer details out.

 

Fingers crossed that it is the bolts.

 

 

 

Hi Rich

use the bolts in my link and follow Johns instruction above - you may be lucky.

 

Just a thought - have you done anything that would cause the bolts to be missing/different.

When did the judder start.

If you have had no work done for some time and then the problem started it may well be the bearing carrier anyway.

 

Roger

Edited by RogerH
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Hi Rich,

You can try the two alignment bolts first.

They have an interference fit, so may require some tapping to get them in. Before you install them, you can feel with a bent hook from wire if the gb/engine is mis-aligned. It will not be much you mau think, since all other bolts also will align the two items, sort off, but not enough.

You can do this without removal of the engine, preferrably with tunnel removed for better access.

Bought mine from Moss, didnt see anything special about them, first instance looked standard 3/8 bolts, but the plain shank is a bit different.

Good luck,

Waldi

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Idea:
I note on ebay-UK there are currently dowell pins for sale, they may be easier to fit than the bolts:

 

https://www.ebay.co.uk/itm/triumph-tr6-gearbox-dowels-tapered-alignment-pins/232929301522?hash=item363bab1412:g:KTcAAOSw38VbnWBd

 

Waldi

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HI Rich

 

If you have not had the gearbox out before this problem started , i would (from recent expierience) go with the advice re clutch release bearing carrier as the problem.

 

However follow John and Rogers advice first, re the alignment, it is the easier one to check.

 

If you need advice on replacement parts speak to Tom at TR Enterprises ,they supplied the correct upgraded parts for mine and sorted the problem.

 

Just a very happy customer.

 

Good luck

 

 

Brian

Edited by brian -r
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Hi Waldi,

they are just for alignment and not permanent use.

Stick with the bolts P/No 132872

 

Roger

Thanks Roger,

You are right.

I did not need them since enine and GB were out.

It may be helpfull for in-situ alignment.

Not much room to tap on the heads, and these tapered pins will make it easier, so the holes are aligned before installing the correct bolts.

Waldi

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Hi

 

First, thanks for all the advice!

 

so this is part two of a clutch problem. I have owned my TR for about 18 months now and had issues of getting it into first and reverse almost from day one and It was just horrible to drive mainly due to the whole mechanism feeling rough and getting into the aforementioned gears. I noticed the master cylinder was leaking and decided to fix that with a mechanic - who put new seals in plus I bought a new slave. It came back better and no issues getting into gear but since getting it back but this problem I describe now has evolved and seems to worsen.

 

So the next stage is these bolts that Roger advises and see how that is? Thanks to such great feedback,

 

Rich

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Hi Rich,

I do not think it is the taper pin as that may cause issues engaging 1st or reverse it shouldn't normally cause judder.

You appear to have described ratchet clutch to a tee.

 

Basically you lift the clutch pedal, the release bearing carrier sticks on the front cover extension snout item #10 https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/clutch-transmission-drivetrain/gearboxes-components/gearbox-units-external-components-tr5-6.html.

With vibration etc the bearing jumps back to catch up with the retracting fork.

 

TR6's suffered this badly in the early days if the alignment bolts (item #17 2 off) were left out or put in the wrong place.

 

So you may be lucky and refit the two alignment bolts - keep GB insitu.

 

However if you are unlucky then the GB needs to come off.

 

Have a very critical look at the snout of the front cover extension - you may see witness marks where the bearing carrier gets stuck.

It could be worth checking the alignment of the snout to the splined GB input shaft - it should be concentric - my 4A GB was 0.015" vertically displaced.

 

Try this test.

With the engine switched off - press the clutch pedal and engage 1st gear. Now lift the clutch - did it feel as if the clutch felt normal.

If you have mis-alignment then this is normal because the release bearing is not being forced out of alignment.

With the engine rotating the release bearing gets thrown out of alignment and the carrier sticks.

 

What release bearing carrier do you have.

For a TR6, steel is normal (I have this on my 4A and it works perfectly)

Many people recommend the Phosphour bronze carrier - but it must be the harder dark yellow (old gold) in colour

The lighter coloured bronze carrier is for saloons and they have a different fork.

 

Good luck

 

Roger

Roger

 

Please excuse my thickness.

 

Is it https://www.moss-europe.co.uk/bolt-dowel-132872.html?assoc=125046 you referring to (2x two of) ? With item number 132872, or item 17 on the diagram? If, so, I can only see one reference or one bolt to item 117 on the diagram. Appreciate your help.

 

Rich

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it is two you require and they should be fitted before tightening any other bolts or nuts that attach the gearbox to the engine back plate

Cheers. . Peter W

 

PS the 2 dowel bolts should be a hand push fit in their holes through the steel backplate and the aluminium bell housing flange. Not hammered in. Best to fit them first.

Edited by BlueTR3A-5EKT
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Rich,

 

when fitting the two dowel bolts/shouldered bolts, make sure that the holes, in the engine block, have not been 'Belled' over, by the previous fitting of the wrong

(Narrower) bolt, this can happen and lead you to believe the holes are too small to take the correct bolts.

 

John.

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The correct part number for the 2 relevant locating dowel bolts appears to be 132872 - these appear to be available from Moss, but Rimmers and some other suppliers are saying this has been superceded and instead GHF106 should be used instead - this appears to have a similar shoulder but a longer thread. Is this really OK to use or is a question of it's a close fit, so it should be OK to use, but in reality not?

 

Is the original dowel bolt a special size in diameter terms to be a tight fit even though it is said to be 3/8th UNF , or is it a standard 3/8th UNF but with a special shoulder?

 

Be interested to know

 

Cheers

Rich

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Hi Rich,

Mine came from Moss, they were not specially machined or so, looked like std 3/8 shouldered bolts, but the shoulder was a bit different in diameter.

The unthreaded portion was a bit short I found, so the thicker aluminium GB flange was not completely filled with a bare shank, but I felt it was sufficient for proper alignment.

It may be because my bell house is the thicker one.

Installed them with head on the thinner steel engine plate side.

Waldi

Edited by Waldi
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Hi Rich

I had the same problem many years ago now about early to mid 80's. There was no easy release of the clutch, tried to drive normally and then bang all of a sudden we were off, nearly taking my head along with it! . It was like I had never driven a car before, most embarrassing !

I remember taking it to the Northern TR Centre and they whipped out the box, inspected the clutch assembly couldn't find anything wrong, put some Copper Slip on a few things and stuck it back together. 3 weeks later the same symptoms returned, as you would expect.

A very clever mechanic friend of mine offered to "have a go" and it was he who discovered the problem. The release bearing, when making contact with the fingers on the clutch cover, was going in at an angle because the fingers were not all in unison with regard to tension. The ones with weaker tension were allowing the release bearing to go in squint thus giving you the "all or nothing" clutch release symptom.

New clutch cover fitted and all was great with the world again. The plate was new anyway so that didn't need replacing.

Hope this helps

Alan G

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Hi Rich,

Mine came from Moss, they were not specially machined or so, looked like std 3/8 shouldered bolts, but the shoulder was a bit different in diameter.

The unthreaded portion was a bit short I found, so the thicker aluminium GB flange was not completely filled with a bare shank, but I felt it was sufficient for proper alignment.

It may be because my bell house is the thicker one.

Installed them with head on the thinner steel engine plate side.

Waldi

Waldi

Thats exactly what I was wondering ie does the Moss dowel bolt have a specially machined shoulder which is slightly larger than a standard 3/8th bolt so its a tighter fit into the bellhousing.

 

If so, my worry is that the suggested replacement of GHF106 is not actually a direct replacement but the closest match in terms of a standard bolt, in which case it's unlikely to work?

 

To avoid confusion with the OP Rich

 

Cheers

Rich CR!

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Hi Alan,

mine was also going in 'squint - must be a Scottish term'.

The cause on mine was that the GB splined input shaft and the bearing carrier extension snout were not concentric - 0.015" vertical displacement.

Gave the same effect as your - bearing and carrier being pushed to a different center than the GB input shaft.

This OK going in and OK when the engine is not turning. When the engine is turning it keeps the bearing on the wrong centre. Then it tries to jam up.

 

I made a tapered skim to go under the GB front extension to align the centres.

 

Roger

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Hi Alan,

mine was also going in 'squint - must be a Scottish term'.

The cause on mine was that the GB splined input shaft and the bearing carrier extension snout were not concentric - 0.015" vertical displacement.

Gave the same effect as your - bearing and carrier being pushed to a different center than the GB input shaft.

This OK going in and OK when the engine is not turning. When the engine is turning it keeps the bearing on the wrong centre. Then it tries to jam up.

 

I made a tapered skim to go under the GB front extension to align the centres.

 

Roger

Hi Roger!

I suffered from ratcheting clutch for 44 years of some sort and it got worse in creeping traffic! When my engine was rebuilt I had a very careful look at the bearing carrier clearance to gear box nose. There was far too much clearance in my view well over .012" its was rocking on the nose. So after finding out that Revington used proper phosphor bronze I ordered one of these, to my surprise there was very little clearance between the two. Therefore it was not wear on the original nose, from memory it was not more than .003". It was a nice sliding fit. On my first drive up the road I could not believe the difference in operation. On Saturday when returning from Kop Hill because of traffic I had to do 20 + hill starts no problem. But ORS also did the saloon slipper conversion as well on the carrier as I feel this also helps with the alinement of the thrust bearing to clutch .

 

Bruce.

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