Inadequate clutch throw

[timpress]

On 3/21/2024 at 6:37 AM, 87bor said:

Have you checked any play at the master cylinder.  The pushrod should be 81mm from end of spigot to the centre of the clevis pin hole.  Also there may be play in the pedal lever.  The hole become oval over time and you lose 5 to 10mm of throw on the pedal.  The photo proves my point.  New master cylinders are sent out with the wrong length push rod. You can go round and around incircles before realising this could be your problem.  Because it's new you assume it must be OK.

Your issue could also be down to a dodgy clutch assembly. 

I live in New Zealand and many of us are  reliant on Rimmer Bros for our parts.  Unfortunately the quality of their items has gone downhill over the years to the point that we are afraid to order from them anymore. We search for old parts at the Vintage Car Club and restore them whenever possible.

You can put up simple things like ill fitting dashboards and door cards, radiator overflow bottles with no thread (so the lid won't stay on), but when you buy their clutch kit and spend months bleeding the hell out of the system trying to get the gears to engage it can become extremely time wasting, frustrating and downright depressing when faced with  having to pull the gearbox out again. 

Luckily we have a clutch specialist in Christchurch who can rebuild clutches to a standard better than the original.  I would recommend anyone with the option to use someone like this as opposed to buying new.  Doesn't matter if it says Laycock or Borg and Beck on the box, that junk comes from China and you will be playing Russian Roulette.  Maybe it works and maybe it doesn't. If you lay an old original borg and beck clutch against a new one you can see the difference in quality. The pressure plate is lighter and the fingers are thinner. Release bearings are again a low quality reproduction. 

I was so fed up with sticky clutches in my TR6 that I ripped the Triumph gearbox and clutch out and installed a Toyota  W58 five speed conversion.  It transformed the car. That was 13 years ago and it has been maintainance free ever since ......and no oil leaks! 

Just like you,  a friend of mine has been going through hell with a new Rimmers Clutch in his newly restored TR5. The car is undrivable.  Having just installed a brand new interior he has to rip the gearbox out and find out why the clutch is so hard and snatchy and won't  engage cleanly. He should take the clutch to the specilist and have it assessed and if it is shown to be substandard consider suing Rimmers. I have always been suspicious that they send seconds or returned items overseas because they know we won't pay the courier fees to return them. 

Go onto the Trustpilot website and look up Rimmers and you can see how dreadful their reviews are. https://nz.trustpilot.com/review/rimmerbros.com.  Just like Booking.com any positive reviews are most likely fake. 
 

Its all fixed now as referenced in the thread, though thanks for replying.

[astontr6]

On 2/17/2024 at 6:50 PM, timpress said:

The bore is .70 as marked on the one I replaced so I know it was a like for like swap.

My advice is do not use a .70 bore size M/C only use a .75 as based on my own experience? Also is the clevis pen hole and  M/C yoke in the clutch pedal oval? I bushed mine with a marine bronze bush 40 years ago and it has still very little play in it.

Bruce.

[Z320]

Hi,

on a proper working clutch of any TR

the clutch disengages after only a small way of travel of the pedal,

with a hudge and needless way of travel until the pedal is down to the floor.

Way enough to use a smaller master.

This is why I used a 0.625“ master without problems for some years.

With my hydraulic throw out bearing I‘m down to a „equal“ of a 0,604" 0.51“ master since 4 (or 5?) years.

This works lovely and I still have enough empty way of needles travel after the clutch disengages.

This is about half piston surface, double pressure and less than half force to press the clutch.

Ciao, Marco 

Edited July 12, 2024 by Z320
calculation was wrong, I'm down on an equal of 0.604"

[BlueTR3A-5EKT]

I am seeking a .625” master cylinder to modify my sidescreen car clutch with.    Will report back once completed.

 

My research says it is a clutch master cylinder for a MGC

Edited July 11, 2024 by BlueTR3A-5EKT

[astontr6]

On 2/18/2024 at 10:07 AM, RogerH said:

Hi John,

I'm sure I read somewhere that there was a conflict in the pictures but not sure which was correct.

 

Roger

The Haynes manual shows that the flange is mounted on the front of the engine back plate bracket, page 97  figure 53 refers!  Are we certain that the taper pin in the cross shaft is not broken? In the past I have seen the M/C push rod modified in an attempt to cure lack of movement, like we have here!.

Bruce

[roy53]

On 3/7/2024 at 5:59 AM, BaulyCars said:

I missed it too at first, but there was a nut in there..., actually quite a nice nyloc one, which I kept for other things

Or you mean its missing something else (apologies if I'm misunderstanding)

Have seen this done on a tour when the clevis pin failed. A knowledgeable one took the TR6 wheel nut which is blind and fitted it in the master .

Perfect fit for rod and cylinder. Drove for 2 weeks it the Alps and back to UK 

Roy

[Andy Moltu]

The reality is the amount of throw required to disengage the clutch is small. (Which is why Marco gets away with a much smaller master cylinder than the standard 0.75" and later 0.70" bore master cylinders) 

The hydraulics on the 6 pots are essentially self adjusting. Wear in the push rods is rarely enough to compromise operation. 

Assuming you have made no changes to the assembly as a whole. New problems with disengagement are either hydraulic - failing seals leaking fluid out or air in. Or mechanical.

Bleeding the clutch will temporarily get rid of the air on a worn system unless the seals are totally shot when significant leakage should be apparent. At the slave end it's usually a combination of wear and corrosion and the master cylinder it's usually just seal wear. Both can be rebuilt with new seals but unless the slave is only superficially corroded it's only worthwhile as an emergency fix. Master cylinders can be rebuilt as corrosion is less likely but replacement ones are so cheap as to make rebuilding them a limited savings. (They are fitted to a lot of other things like trailer brakes but you may need to reuse your pushrod if the repro is different.

By all means change them but when you have done so and eliminated these the odds are it's the clutch pin. They eventually suffer from stress fractures and you are left with a stump that grips enough at first with the operating lever rotating only slightly on the clutch shaft. Eventually this wears away and more and more movement resulting in the clutch not disengaging. 

The pressure plates can wear but usually wear results in slippage. Catastrophic failure that prevents disengagement tends to give a rock solid pedal. 

Like the broken pin it's time for gearbox removal. A time consuming pain in the behind but the odds are this is where you are heading and it's better to do it now rather than have the car fail when you want to use it in the summer. Replace the pin and the clutch as a whole - cover, driven plate and release bearing. I would advocate using an uprated release bearing. Robsport sell them cheaply enough on eBay as the standard release bearings are a bit hit and miss in terms of longevity. (It's a Japanese Koyo bearing used by some Toyota's rather than the RHP of which there are still quality issues in the supply chain)

I'm planning to replace the juddery clutch on my 6 next week if it warms up. (Before anyone says it's not a lack of dowel bolts but a dud rebuilt Laycock unit) Will post some pics.

[Paul Hig]

My clutch ended up operating at floor level. No bleeding of system or adjustable rods helped

Usual suspect to blame, so now GB out, new pin, fork, rod, slave cylinder, rear crank oil seal, box selector oil seals and new clutch on refaced flywheel 

Edited March 30, 2025 by Paul Hig

[stuart]

15 minutes ago, Paul Hig said:

My clutch ended up operating at floor level. No bleeding of system or adjustable rods helped

Usual suspect to blame, so now GB out, new pin, fork, rod, slave cylinder, rear crank oil seal, box selector oil seals and new clutch on refaced flywheel 

Don’t forget to cross pin the fork before putting it all back 

Stuart

[Paul Hig]

On 3/30/2025 at 4:29 PM, stuart said:

Don’t forget to cross pin the fork before putting it all back 

Stuart

Have got that sorted, along with refaced flywheel, new clutch, new crank rear oil seal, new selector fork oil seals

Hope all will be back in car by mid next week as MoT due on 11th!!

[JohnC]

No harm in putting in two cross shaft bearings each side while you're at it, rather than just one. 

[CeeJay]

I have the same problem. Short throw & leaking Clutch Fluid.

Looks like Master Cylinder is Girling 61676310 (0.75" bore?), but the Slave is 1" bore.

Should Master & Slave both be the same bore???? Help Please, thanks

[CeeJay]

Maybe  Girling 64676310 

[stuart]

1 hour ago, CeeJay said:

I have the same problem. Short throw & leaking Clutch Fluid.

Looks like Master Cylinder is Girling 61676310 (0.75" bore?), but the Slave is 1" bore.

Should Master & Slave both be the same bore???? Help Please, thanks

No those bore sizes are correct.

Stuart.

[Tim T]

On 4/8/2025 at 5:26 PM, RobH said:

I assume the fuel gauge is reading normally, which eliminates the gauge voltage regulator?  If both gauges don't read, the regulator or the connection to it is duff. 

If that is OK, take the lead off the temperature sender and earth the lead. With the ignition on,  the gauge should go full-scale to hot.  (best to first take the power supply lead off the coil  to prevent cooking it and/or any electronic ignition if that is fitted.)  

If the gauge does not budge the fault may be the wire connection, or the gauge itself. Most likely the wire which could have broken near the spade connector where it can waggle. 

 

On 3/30/2025 at 4:12 PM, Paul Hig said:

My clutch ended up operating at floor level. No bleeding of system or adjustable rods helped

Usual suspect to blame, so now GB out, new pin, fork, rod, slave cylinder, rear crank oil seal, box selector oil seals and new clutch on refaced flywheel 

Paul,

Was that an old pin or from a reconditioned box?

I still have a similar issue on a box rebuilt by one of the reputable companies who say that they have not heard of one of their pins breaking. I really don't want to remove the box to find that the pin is intact.

Thanks,

Tim

Edited April 10, 2025 by Tim T

[Z320]

Hi,

last Saturday my mate Michael was in my garage with his 3A.

On his gearbox the pin through the shaft is broken, but that works anyway.

Because it rests in a new position and the push rod from the slave to the lever is suitable adjusted to this situation.

His problem with not enough travel very likely is the not proper closing valve in the clutch master.

This is why we will fit a new one tomorrow, with 0.625“ bore (was in my workshop already).

Ciao, Marco

[Paul Hig]

21 hours ago, Tim T said:

 

Paul,

Was that an old pin or from a reconditioned box?

I still have a similar issue on a box rebuilt by one of the reputable companies who say that they have not heard of one of their pins breaking. I really don't want to remove the box to find that the pin is intact.

Thanks,

Tim

Box was in the car when I bought it. Reserch shown that it is a weak point in the system and that if other adjustments don't work, you have no choice other than to take the box out and change the pin. On mine I took the opertunity to skim the flywheel (shout out to Lancaster Engines in Morecambe for a great job) new clutch, new release bearing, carrier, rod, slave cylinder. Also cross drilled shaft and inserted roll pin as extra protection as advised by those that Know   

Your 5's and my 6 share the same engine (CP series) and gearbox set up. I went through every option to not take the box out, as suggested on here and by the gurus of Cumbria TRR, but had to give in and change the pin. A lot of "blue air" for a 50p part!!

[Richard B 2.5PI]

On 4/4/2025 at 11:36 AM, JohnC said:

No harm in putting in two cross shaft bearings each side while you're at it, rather than just one. 

Chris Witor sells extra wide cross shaft bears as an alternative to fitting two. I'm sure other supplier do as well.

[Z320]

Hi,

the valve and seat both have been without visible damages,

but the new 0.625“ master cured the problem and Michael is delighted how easy the pedal goes!

Ciao, Marco 

btw

a not proper closing valve in the clutch master I do not remember to be mentioned anywhere

Edited April 13, 2025 by Z320

[Jules TR6]

What is the conclusion of this pinned topic?

1. Master cylinder may need replacing (and slave) due to leaking seals.

2. The taper pin in the selector fork may be broken.

3. Master cylinder pushrod is about 10mm too short on new replacements (for some reason RHD cars need a longer pushrod?).

___________________________________

1 and 2 are due to failures, number 3 is due to the incorrect part being supplied to all of us.

This is important, are the pushrods in most new master cylinders, sold for the TR6 in the UK, too short? - so many people re-use the old pushrods from cylinders of the 1960's (if they are lucky enough to have them).

My new master cylinder pushrod has about 10mm of ridiculous back and forth slop to the pedal - I'm thinking why isn't this pushrod longer? - it's causing problems.

What to do? Rimmer sells a replacement pushrod (made of thicker metal at the pedal end so requiring a longer clevis pin), is this pushrod longer - a workaround solution to the problem? - or is it just the same shorter length? https://rimmerbros.com/Item--i-122296

[BlueTR3A-5EKT]

7 hours ago, Jules TR6 said:

What is the conclusion of this pinned topic?

1. Master cylinder may need replacing (and slave) due to leaking seals.

2. The taper pin in the selector fork may be broken.

3. Master cylinder pushrod is about 10mm too short on new replacements (for some reason RHD cars need a longer pushrod?).

___________________________________

1 and 2 are due to failures, number 3 is due to the incorrect part being supplied to all of us.

This is important, are the pushrods in most new master cylinders, sold for the TR6 in the UK, too short? - so many people re-use the old pushrods from cylinders of the 1960's (if they are lucky enough to have them).

My new master cylinder pushrod has about 10mm of ridiculous back and forth slop to the pedal - I'm thinking why isn't this pushrod longer? - it's causing problems.

What to do? Rimmer sells a replacement pushrod (made of thicker metal at the pedal end so requiring a longer clevis pin), is this pushrod longer - a workaround solution to the problem? - or is it just the same shorter length? https://rimmerbros.com/Item--i-122296

Jules, we did this earlier in this pinned thread.

How about you buy a cylinder with a threaded push rod and suitable clevis then adjust to suit?

https://www.carbuilder.com/uk/07-brake-and-clutch-master-cylinder-with-reservoir

https://www.carbuilder.com/uk/516-master-cylinder-clevis

 

For the push rod why not make an adjustable one.?  You will then be able to adjust out most of the wear at the pedal, and have a push rod that actuates the cylinder as near directly as is practicable when the pedal is pushed.

TR3 Girling hydraulic system cars used it on their master cylinders, which are the same design master cylinder as fitted to TR5/250/6 clutch.    

A threaded pushrod, which is also used on older Land Rovers is under a tenner.   You could probably even use a mushroom headed roofing bolt!

 https://racingcult.co.uk/products/replacement-master-cylinder-push-rod.html   

All you will need then is a clevis fork end that will thread onto the push rod.  Plus a lock nut.

 

https://www.retroford.co.uk/product/push-rod-clevis-5-16-unf-for-master-cylinder/

 

Edited August 14, 2025 by BlueTR3A-5EKT

[Jules TR6]

Many thanks for setting out the above - very clear.

BTW what is the normal 'free-play' at the end of the pushrod that should be aimed for? - I assume there should be some slight back-and forth movement (2 or 3mm's?) so the system is 'relaxed' when the pedal isn't pressed.

Edited August 14, 2025 by Jules TR6

[Andy Moltu]

On 4/10/2025 at 4:47 PM, Tim T said:

 

Paul,

Was that an old pin or from a reconditioned box?

I still have a similar issue on a box rebuilt by one of the reputable companies who say that they have not heard of one of their pins breaking. I really don't want to remove the box to find that the pin is intact.

Thanks,

Tim

That assumes they replaced it - easily overlooked or omitted if new one not at hand.

[Waldi]

2 hours ago, Jules TR6 said:

 

BTW what is the normal 'free-play' at the end of the pushrod that should be aimed for? 

The TR6 (and I think also the TR5) slave cylinder has an internal spring fitted in the bottom of the cylinder which pushes the piston out with a light force. The result is no/minimal play and a “self-adjusting” clutch.

Waldi

[BlueTR3A-5EKT]

8 hours ago, Jules TR6 said:

Many thanks for setting out the above - very clear.

BTW what is the normal 'free-play' at the end of the pushrod that should be aimed for? - I assume there should be some slight back-and forth movement (2 or 3mm's?) so the system is 'relaxed' when the pedal isn't pressed.

Yes you need free movement at the master cylinder 1 mm will do. So long as there is no force on the cylinder piston by the push rod/pedal.  If there is, the piston in the cylinder will not clear the internal ports, holding fluid pressure in the hydraulic circuit.   
The spring in the slave cylinder (if fitted) keeps the slave push rod extended    It has no action on the master cylinder if the piston clearance of the master cylinder is maintained    

Edited August 14, 2025 by BlueTR3A-5EKT