Sticky Clutch syndrome; Which clutch to replace it with?

[SlickV8]

Hi all, I've just finished my first TR6 build and 200 miles into an [otherwise brilliant] shakedown run its developed what I believe is referred to as Sticky Clutch Syndrome. The pedal is fine and smooth with the engine off but as it warms up the clutch become increasingly sticky as it comes up making pulling away somewhat awkward. Having just had my first weekend in 12 months without oil under my fingernails I'm resigned to now stripping her again & removing the 'box to replace it...but what with? Ive no idea what clutch is in it, it was an abandoned project and the PO had insisted he'd put a new clutch in so I left it untouched [that'll teach me!]

From what I can find, the B&B aftermarket clutch can be the cause of this but theres also a B&B Original Spec and one thats described as B&B OEM. The best solution seems to be the Laycock clutch but they seem to be unobtanium. 

I really only want to do this once so advice would be most gratefully received?

Thanks

[RobH]

Are you sure it's the clutch and not bell housing misalignment or the release bearing carrier binding on the gearbox 'nose'? 

 

[RogerH]

Hi Slick,

in  general there is nothing wrong with the B&B products as such.

The sticky clutch (ratchet clutch)  is caused by the engine and GB centrelines not being aligned.

During the rebuild did you fit the two special bolts that hold the bellhousing to the engine backplate.  ?

These align the two lumps.

On my 4A I found an oddity - the splined GB input shaft was ata slight angle (apprx 15') in the vertical axis.  

This caused the Clutch Bearing Carrier to be on the 'cock' - which allowed the carrier to snag/stick on the GB extension and then suddenly release.

Look for wear marks on the extension nose

Roger

Edited August 14, 2023 by RogerH

[SlickV8]

I'm as sure as I can be from doing a bit of research, I've not removed it as the symptoms seem to be exactly as people describe Sticky Clutch Syndrome. TBH at this point in the build I'm thinking for the sake of a few hundred £ and a days hard labour I may aswell just replace the clutch and be done with it

[SlickV8]

6 minutes ago, RogerH said:

Hi Slick,

in  general there is nothing wrong with the B&B products as such.

The sticky clutch (ratchet clutch)  is caused by the engine and GB centrelines not being aligned.

During the rebuild did you fit the two special bolts that hold the bellhousing to the engine backplate.  ?

These align the two lumps.

On my 4A I found an oddity - the splined GB input shaft was ata slight angle (apprx 15') in the vertical axis.  

This caused the Clutch Bearing Carrier to be on the 'cock' - which allowed the carrier to snag/stick on the GB extension and then suddenly release.

Look for wear marks on the extension nose

Roger

I dont recall any 'special bolts' but it was a long time ago in the scheme of things; I'm just on line now looking to see if I can find them; would you suggest replacing them with new ones, refitting the 'box to the engine and trying? could it be that simple?

[RogerH]

Hi Slick

have you got a name ?

See item 117   Here   fitted in two places.

If it is just bolt replacement, then slacken off ALL attachment bolts fit the Dowel bolts and then re-tighten all bolts.  No need to remove GB.

They are positioned apprx 2 & 10-o-clock. (I think)

 

Roger

[Iruka]

Hi, the part number for the dowel bolts is 132782. Obtainable from Moss or TRGB. 2 needed.

[RogerH]

33 minutes ago, SlickV8 said:

I'm as sure as I can be from doing a bit of research, I've not removed it as the symptoms seem to be exactly as people describe Sticky Clutch Syndrome. TBH at this point in the build I'm thinking for the sake of a few hundred £ and a days hard labour I may aswell just replace the clutch and be done with it

...but it is not the clutch  or its components.

Roger

[SlickV8]

Thank you all, Its got to be worth a go  I'll order them now

regards

Nick

[BlueTR3A-5EKT]

10 minutes ago, SlickV8 said:

Thank you all, Its got to be worth a go  I'll order them now

regards

Nick

Nick,

 As Roger has stated.

You must slack off all the gearbox attachment bolts before attempting the fit the two dowel bolts.  Do not just smack them in as that will damage/enlarge the tolerance sized holes in the gearbox and engine back plate and you will be back where you started, but now need a back plate and bell housing.

[TRTOM2498PI]

On 8/14/2023 at 10:10 AM, SlickV8 said:

Hi all, I've just finished my first TR6 build and 200 miles into an [otherwise brilliant] shakedown run its developed what I believe is referred to as Sticky Clutch Syndrome. The pedal is fine and smooth with the engine off but as it warms up the clutch become increasingly sticky as it comes up making pulling away somewhat awkward. Having just had my first weekend in 12 months without oil under my fingernails I'm resigned to now stripping her again & removing the 'box to replace it...but what with? Ive no idea what clutch is in it, it was an abandoned project and the PO had insisted he'd put a new clutch in so I left it untouched [that'll teach me!]

From what I can find, the B&B aftermarket clutch can be the cause of this but theres also a B&B Original Spec and one thats described as B&B OEM. The best solution seems to be the Laycock clutch but they seem to be unobtanium. 

I really only want to do this once so advice would be most gratefully received?

Thanks

This is known as a 'ratchet clutch' symptom.  Fine when operated when the car is cold, but worse once everything expands and gets warm.  I had the same issue circa 20 years ago.  It transpired that the nose piece that comes off the gearbox, where the clutch release fork runs back and fourth, was slightly out of alignment, made worse once warm and expansion.  With a new nose piece, the clutch was silky smooth again.

 

Obviously also make sure you still have all the dowels fitted.

The issues with B & B clutch plates is now a thing of the past, as there was a bad batch around 20 years ago, where there was only 3 rivets holding the centre plate to the friction material. I know, I ripped one to bits at full throttle in o/d 3rd on the way to Brands Hatch !

 

Good luck.

 

Edited August 15, 2023 by TRTOM2498PI

[TRTOM2498PI]

Below may also prove useful:-

I had a sticky clutch in my TR250 and after I mentioned it to some of the Buckeye Triumphs members I found Murry Mercier had a similar problem. I’ve also seen a number of references to the problem on the Triumph and 6-PACK email lists. The symptoms are that the clutch sticks and then jumps when engaged. As the pedal is released, the back force on the pedal decreases to zero and hangs briefly and then jumps back. The clutch goes from not engaged to nearly fully engaged. We’ve dubbed this the binary clutch. This makes for jump-starts like those of a beginning driver. Another symptom observed by Murry (and others) was a "squeal" or "chirping" except when the clutch pedal was depressed. History: The problem on my TR250 first showed up about 10 years after a new clutch was installed but after only a couple thousand miles or less of operation. The clutch disk and pressure plate are Borg & Beck with the standard release bearing. The gearbox was pulled a couple years ago to free the clutch disk. At that time everything in the clutch area was inspected and fresh grease applied to the release-bearing sleeve. The clutch operated smoothly when the engine was cold and then started to stick after about 20 minutes of operation. After the engine was hot, the clutch disengagement also seemed a little rough; when the pedal was pressed it felt like there was an abrasive somewhere in the system. Murry was using the TRF “Magic Clutch” with the upgraded release bearing and sleeve and new clutch fork and operating shaft. As in my case, his clutch hung up as the pedal was released and then let go causing the clutch to go from released to engaged instantly. His problem showed up about 500 miles after the clutch was installed and was sticking all the time, even when the engine was cold. He also pointed out that his operated smoothly when the engine was not running. I found that hard to believe. I then ran my TR250 till it was hot and the clutch stated to stick, then shut it off and found the clutch was then smooth. Still not believing it, I repeated the test several more times with an even hotter engine ---- same results. Find the root cause: Most folks, when they encounter a clutch problem and go to the effort of pulling the gearbox, replace everything in sight. In my case, I wanted to fix the clutch so that I could use the car occasionally for the next year of so at which time I plan to pull the engine in conjunction with a new paint job. Since the clutch components had little wear, I decided to try to find exactly what was going on, fix only the source of the problem, and change nothing else. Murry was on his third clutch with each exhibiting the same symptoms. Numbers 1 and 2 had less than a few thousand miles on them before they were replaced, so he was not anxious to replace parts for a fourth time. The replacement of new parts with #3 included the magic Clutch Kit and all related parts including: bushing, shaft, fork, pin, arm, and pilot bushing, which was "staked" and pressed into place. Expert Advise: In the fall of 2000 I stopped at TRF on my way back from vacation. I asked the “technical expert” about the sticky clutch. He suggested the sticky clutch was caused by the release-bearing sleeve hanging up on the gearbox front end cover (the piece it slides over). I readily accepted this since I had reached the same conclusion. The explanation of why it shows up after use was that there is insufficient clearance between the sleeve and front end cover and with wear, particles from the clutch surface mixed with the lubricant making it sticky and prone to grab rather than slide. The explanation for my clutch sticking only after it is hot was that the sleeve and front end cover change dimensions differently as they get hot causing the clearance between the two to reduce. I’ve heard several stories of people cutting large holes in the bell housing so they can lubricate the front end cover to keep the sleeve from hanging. At first I thought that was pretty dumb. However, if one has pulled the gearbox several times without finding a permanent fix, a lubrication access port might be considered an innovative solution. The point here is that fresh lubrication of the front end cover stops the sticking for a while indicating that the problem is indeed caused by the sleeve hanging up on the front end cover. The solution to these problems suggested by the TRF expert was to make sure that the cold clearance between the sleeve and the front end cover is .015 inches. Sleeve Clearance Measurements: Shortly after my visit to TRF Ryan Miles, another Buckeye Triumpher, was ready to install the clutch in his ’74TR6. We decided to do a little research on the sleeves and front end covers we had before he did the installation. We measured several sets of sleeves and front end covers. The outside diameter of the several front end covers were within .001 inches of the same size. We measured several old and one new sleeve. The old sleeves (all of which were thought to have worked well) gave a clearance of between .005 and .010 inches while the one new sleeve was smaller and gave a clearance of only .002 inches. We also noted that the new sleeve was hardened whereas the old sleeves were not. At the time Ryan and I thought the .015-inch clearance was over kill and decided that a clearance of .008 to .010 inches should be OK since I was convinced that the problem with my TR250 was that I had installed a new sleeve that was too small. Inspecting the TR250 Parts: I finally got around to pulling the gearbox and checking out the TR250 clutch in late January, 2001. After the clutch was removed it was checked for wear; there seemed to be little or none --- not surprising since it had only a few thousand miles of use. It was the old style Borg & Beck, the one that is much stiffer than the wimpy Laycock clutches used on the later TR6s. The gearbox front end cover and release-bearing sleeve were then examined. The sleeve was one of the older styles that had not been hardened. As mentioned earlier, about three years ago I started the car after it had sat for five or six years and found that the clutch plate was stuck to the flywheel. The gearbox was removed to free the clutch plate and the sleeve and front end cover were cleaned and lubricated. The clutch started sticking sometime after that. The car has been driven less than 1,000 miles since freeing the clutch. The following photo shows the front of the gearbox with the release bearing, sleeve, gearbox front end cover and the operating shaft with clutch fork attached to refresh your memory. When the clutch petal is pressed, the operating shaft rotates such that the top of the fork moves toward the front (right) and pushes the sleeve and release bearing against the clutch pressure plate (that is not shown)

[Schnippel]

Hello,
the carrier for the release bearing should be turned 0.5-0.8 mm larger in diameter. The carrier then wobbles on the nose of the gearbox input shaft! Now the release bearing can center itself on the membrane spring!
No more jerking clutch.
Best regards
Ralf

[SlickV8]

Thanks all. There’s some reading in that lot

I’ve ordered new locating dowels, a new release bearing & a new bronze sleeve. They won’t be delivered before I have to go sit on a beach (wishing I was in the garage) for a week but I’ll report back with the results as soon as I can get to it. 

[RogerH]

23 hours ago, TRTOM2498PI said:

 

Hi Nick,

 have an excellent holiday

Before you take it to pieces fit the dowel bolts (correctly)  it may save time and effort.

 

Roger

[jamesStag]

Hi Nick,   

I can concur with what Roger has advised. My father's Triumph V8 Stag had exactly the same problem of ratchet clutch after a rebuild. It became undriveable when warm. Whilst it's not identical, it has very similar clutch and gearbox. We actually slackened off all the bell housing bolts till just loose. Gently supported the weight of the box, started up the engine and actuated the clutch a few times, nipped up 2 easy bolts to hold. The stopped the motor and bolted all bell housing bolts up again. Clutch was then smooth as butter and has been for the last 8+ years... 

Good luck,. cheers J.

[Z320]

On 8/14/2023 at 4:01 PM, Schnippel said:

Hello,
the carrier for the release bearing should be turned 0.5-0.8 mm larger in diameter. The carrier then wobbles on the nose of the gearbox input shaft! Now the release bearing can center itself on the membrane spring!
No more jerking clutch.
Best regards
Ralf

+1

My bronze carrier had only 0.3 mm play and worked lovely, but I agree with Ralf:

some more play is better and this is the way other producers go.

I remember noticeable play on the carrier on the MX5 gearboxes I worked on

[Z320]

On 8/15/2023 at 3:23 PM, SlickV8 said:

Thanks all. There’s some reading in that lot

I’ve ordered new locating dowels, a new release bearing & a new bronze sleeve. They won’t be delivered before I have to go sit on a beach (wishing I was in the garage) for a week but I’ll report back with the results as soon as I can get to it. 

Take care it is really made from bronze (golden) and not brass (yellow)

Ciao, Marco 

 

[astontr6]

On 8/14/2023 at 10:10 AM, SlickV8 said:

Hi all, I've just finished my first TR6 build and 200 miles into an [otherwise brilliant] shakedown run its developed what I believe is referred to as Sticky Clutch Syndrome. The pedal is fine and smooth with the engine off but as it warms up the clutch become increasingly sticky as it comes up making pulling away somewhat awkward. Having just had my first weekend in 12 months without oil under my fingernails I'm resigned to now stripping her again & removing the 'box to replace it...but what with? Ive no idea what clutch is in it, it was an abandoned project and the PO had insisted he'd put a new clutch in so I left it untouched [that'll teach me!]

From what I can find, the B&B aftermarket clutch can be the cause of this but theres also a B&B Original Spec and one thats described as B&B OEM. The best solution seems to be the Laycock clutch but they seem to be unobtanium. 

I really only want to do this once so advice would be most gratefully received?

Thanks

I suffered from sticky clutch for years until a TR garage told me what it was and what was causing it. I changed the bearing carrier to a bronze one along with the slipper pins as used by the saloon cars.  Problem gone that was 6 years ago and I drive in London traffic. Parts were bought from Revington.

Bruce.

[Tim D.]

5 hours ago, astontr6 said:

I suffered from sticky clutch for years until a TR garage told me what it was and what was causing it. I changed the bearing carrier to a bronze one along with the slipper pins as used by the saloon cars.  Problem gone that was 6 years ago and I drive in London traffic. Parts were bought from Revington.

Bruce.

Interesting what you say about saloon slipper pins.. I have similar on my stag. Looks like a more elegant solution compared to the round pins. 

[Z320]

The diameter of the fork pins must be smaller, ergo pins or fork change.

Or you make your own „TR-pin“ suitable, but I don’t expect this helps with a sticky clutch.

Edited August 19, 2023 by Z320

[Z320]

My mate Wolfang had also problems with his TR6 sticky clutch,

one of the reason was his flywheel, it had „hot spots“ on its surface, making it different hard and not leveled.

The surface locked like cut oak with it „scares“, so deep, not possible to get out with a milling machine.

 

This photo is borrowed from ebay and may illustrate what I mean 

https://www.ebay.co.uk/itm/373395099044

 

 

Edited August 19, 2023 by Z320

[astontr6]

4 hours ago, Tim D. said:

Interesting what you say about saloon slipper pins.. I have similar on my stag. Looks like a more elegant solution compared to the round pins. 

The slipper pins are considered a far better solution than the round pins by the experienced rated TR garages. I have had no trouble with this mod. When I rebuilt my engine I did take all the play out of the clutch linkage, The clevis pin hole in the clutch peddle was worn oval with plenty of slack and wobble. That was bushed with marine bronze which is very hard wearing. Clevis pin clearance was done to absolute minimum clearance.

Bruce.

[Schnippel]

 

Edited August 21, 2023 by Schnippel

[SlickV8]

Got back on it today and typically there’s good news and not so good. 
First off it’s def a Laycock clutch but the previous owner had used bolts instead of locator studs along the top and also put the remaining bolts in from the engine side so the thread was supporting the bell housing rather than the plain steel ‘ring’ at the top of the bolts. 
I had thought the release bearing was noisy so swapped it out for new Koyo one along with a bronze sleeve/carrier. I also don’t know if I should push the bearing into the carrier so elected to push it in as far as I could get it by hand. It looked straight and assuming the clutch pressure would force it further as it operated I reassembled. 
Good news is the clutch works and 20 minute drive showed no sign of sticky syndrome. Still seems a lot of bearing noise in neutral though?

Less good is it has some judder on take up in first & reverse and worse still it’s started dripping oil, quite heavily really  

Im thinking I need maybe press the release bearing further into the sleeve to cure the judder? and that I must have somehow dislodged the main shaft oil seal when putting it back in position?

At least I’m now able to remove a ‘box by myself in around 45 minutes!