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Laycock Clutch Assembly


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19 hours ago, TonyC said:

Hi folks,

just a quick update - found a Laycock clutch assembly ( new old stock) at TR Shop, thanks for the tip kc. Eye wateringly expensive but hey you can’t take it with you! I’ll do without the caviar for a couple of weeks. Added a few other goodies to the order, as you do, so will get into the re-build soon although won’t be able to test drive quite yet as up here in the frozen north we have lots of salt on the roads.

Thanks for all your input. Much appreciated. Stay safe.

TonyC

 

 

Tony,

If you are replacing a Laycock clutch cover stop reading.

If not then be sure to check the 6 attachment bolts of the cover to the flywheel screw in full depth into the flywheel.  B&B has a thicker flange than Laycock and thus different length bolts were specified.  
Failure to get the bolts in fully will mean the clutch cover is not properly clamped to the flywheel and the thing will rattle and not hold the friction plate properly.

 I have just drilled and tapped (5/16 unc) my flywheel deep enough for the longer bolts and fitted a Laycock cover. (Thank you Roger)

Edited by BlueTR3A-5EKT
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Yes Bruce,

the modification from the TR4A to the TR6 pedals and clutch mechanism sadly is a bit „unfortunate“.

If you browse the web for problems you find only questions from TR6 drivers.

Edited by Z320
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Hi Peter,

Many thanks for that heads up. This forum never ceases to amaze me. I had read about this in my long research into this clutch problem - I think it was in Roger Williams book about ‘How to improve the TR6’, but that you already knew such a detail is appreciated. I might just get some new bolts - they are only tightened to 20 ft/lbs so high tensile maybe not required. Anyway I’m on it. Thank you so much.

kind regards,

Tony

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5 hours ago, TonyC said:

Hi Peter,

Many thanks for that heads up. This forum never ceases to amaze me. I had read about this in my long research into this clutch problem - I think it was in Roger Williams book about ‘How to improve the TR6’, but that you already knew such a detail is appreciated. I might just get some new bolts - they are only tightened to 20 ft/lbs so high tensile maybe not required. Anyway I’m on it. Thank you so much.

kind regards,

Tony

I know this because I used to sell both clutch types and needed to get it right for the owner who was going to be replacing their clutch on a Sunday night with hope of driving the car to work on Monday morning.

The Laycock bolts are specified as 5/8” long all others use 3/4”.   Both are 5/16”unc.   
 

I put this info in the Moss sales catalogues.

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  • 3 weeks later...

Hi all,

I now have the NOS Laycock clutch pressure plate and relined friction plate ready to be fitted to the flywheel. I thought I would check a few dimensions and share my observations:-

Friction Plate:- The B & B plate I took out after 30000 miles, had 40 thou of friction material above the rivet heads.  The Laycock plate I have just had relined has 50 thou. Draw your own conclusions.

More interestingly when I checked the thickness of the material that each cover plate is made from, at the fixing holes, the Laycock assembly is 0.240 inches and the Borg and Beck, 0.126 inches. Looking at the construction of each the Laycock has double material thickness at the fixing holes whereas the B & B has only one. This is where the required change in length of the fixing bolts come from. Based on these dimensions the Laycock unit being thicker requires the longer 3/4" bolts whilst the B & B unit requires the 5/8". In any case the bolts I took out, fixing the B & B clutch were 3/4", so I am assuming PO drilled and tapped the flywheel holes deeper.

Overall the B & B assembly I took out is in really good condition and even after 30K miles based on what I see I would have had no hesitation in refitting it apart from the other failures I have experienced in the clutch 'chain', and of course the heavy peddle, which is what I am trying to eliminate. We'll see how successful I have been once everything is re-assembled. Fingers crossed and I will of course come back to you with the final verdict once I have completed a test drive - nearer spring!

Thank you all for your input. Ralf, the Sachs kit is mentioned in one of the documents I read - 'To Laycock or Not to Laycock' by Brent Kiser and he reported similar problems in terms of operating forces. Having said that his paper was published in 1980 and one heck of a lot has changed since then.

TonyC

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I notice Brent mentions in his article that the pivot pins on the original B&B Covers are the key issue as regards pedal pressure in his opinion.

I've got a NOS version of the B&B Cover fitted now and it has this feature, as does the now recommended Sachs Cover I see. The later B&B one I removed doesn't and was, indeed, much heavier.

By the way, the article is from 2000 (his degree was awarded in 1980) but it's still a long time ago now of course.

 

Andrew

 

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The magic clutch setup, now sold by TRF, was a big item here in the USA in the late 90's. It included a Sach's pressure plate from a '79 to '90 non turbo 2L Saab 900 (part # SC436); a throw out bearing from a '75 - '86 Toyota Land Cruiser; and any TR 6 friction disk. Below is TRF's write up on their magic clutch and a great write up on TR Clutches by the Buckeye Triumph Club (great tech articles):

https://trf.zeni.net/TR6-TR250GB/155.php

https://www.buckeyetriumphs.org/clutch

 

 

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I am in the process of removing the GB in my '73 6 due to oil contamination - that's another matter !

I have been using refurbished Laycock covers for 20 years with different release bearings. I managed to obtain 3 duff RHP bearings that failed miserably in the late 90's - one at a mere 120 miles. So I am very reluctant to use them again, although I understand they are used by folks now reasonably successfully.

The latest setup was a rebuilt Laycock cover, an AP Racing plate ( which has additional copper within the friction material - called Organic) and a bearing kit from Herr Gunst of Heidleberg. Sadly this gentleman has passed on and the bearings have no makers marks at all. So I only have the dims - 74mm OD 45mm Id and a thickness of 15mm. Not having much joy in obtaining a replacement. It looks like I will have to use the Toyoto L/C bearing. The issue with these are 'planeing' or groveing of the clutch fingers. I don't believe this is because the setup was not correct, it is just how it is. The Gunst set up was brilliant, it used a modern bearing with a spring which pulled the operating lever back with a low load to ensure the bearing ran in contact with the cover fingers - apparently like modern bearings in fact are designed to do. Gunst also supplied a phosphor bronze carrier as the ID was slightly larger than standard.

So the issue ( for me ) is not obtaining either rebuilt or original Laycock covers or plates ( all readily available - just ask around ) it is which bearing to use. I don't want to go down the route of changing the overall clutch set up, and don't really want to take the box out in 5 years time even Anno Domini  allowing !

It is interesting that the article from the Buckeye site was looking the see 100k miles objective and they were in favour of the Gunst set up......

Views welcomed!

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  • 2 weeks later...

Martin,

The B&B clutch I removed (30k miles) was used in conjunction with a Koyo thrust release bearing and whilst there was evidence of some of the lubricant being flung out of the cage of the bearing onto the inner surface of the bellhousing, there was no significant grooving of the clutch cover plate fingers. I’ve decided to use a new Koyo bearing with the Laycock set-up, but also worth mentioning that I have the Revington adjustable slave push rod and spring which is designed to pull the bearing away from the clutch fingers so there is no contact unless the clutch pedal is operated.

TonyC 

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On 2/19/2022 at 8:04 PM, AWM said:

 

I notice Brent mentions in his article that the pivot pins on the original B&B Covers are the key issue as regards pedal pressure in his opinion.

I've got a NOS version of the B&B Cover fitted now and it has this feature, as does the now recommended Sachs Cover I see. The later B&B one I removed doesn't and was, indeed, much heavier.

By the way, the article is from 2000 (his degree was awarded in 1980) but it's still a long time ago now of course.

 

Andrew

 

You have to be careful when say its a B & B because B & B disappeared as a manufacture some years ago! The name B & B was bought by Firstline and they use the B & B name to fool people its a genuine B & B which it is not. Then we had the 8 rivet saga from them, instead of 16 as per original? I got caught out on this when my lining fell off leaving me with no clutch? This problem has since been corrected by Firstline.

Bruce

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All complete and fully installed. Definitely a lighter clutch action. I moved to a 7.8" diameter slave cylinder to a) get a longer reach with the push rod and b) because I had it and it was new. The change of slave gave a very slight increase in operating force as you might expect but still hugely more comfortable than the previous set-up. I'll take this as a success.  Now just need to get it all run-in a little, re-adjust the free play and move on to the diff next!

Many thanks. Appreciate all comments and input which as usual is extremely helpful and valuable.

TonyC

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  • 2 weeks later...
On 3/13/2022 at 9:13 AM, astontr6 said:

You have to be careful when say its a B & B because B & B disappeared as a manufacture some years ago! The name B & B was bought by Firstline and they use the B & B name to fool people its a genuine B & B which it is not. Then we had the 8 rivet saga from them, instead of 16 as per original? I got caught out on this when my lining fell off leaving me with no clutch? This problem has since been corrected by Firstline.

Bruce

NOS original B&B - they are still out there if you look and can be patient, as are Laycock also of course.

Andrew

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11 hours ago, AWM said:

NOS original B&B - they are still out there if you look and can be patient, as are Laycock also of course.

Andrew

Unfortunately the buying out of British owned companies in the 1980's was common practice and then close them down, use the name and transfer the order book to another country? The Germans were very good at it! 

Bruce.

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7 hours ago, astontr6 said:

Unfortunately the buying out of British owned companies in the 1980's was common practice and then close them down, use the name and transfer the order book to another country? The Germans were very good at it! 

Bruce.

Not only the Germans- look at MG.

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