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Release bearing for B&B clutch cover


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I'm sorry to drag this up again, but didnt find some good info,  which is the best release bearing to use and where can it be bought from.

I know there are some good results with the Toyo bearing, but it does seem to wear the clutch fingers, I'm considering removing the slave cylinder internal spring, presumably it would help the RHP bearing as well?

Is there not a bearing that would touch the inner end of the release levers, and perhaps make the pedal pressure a bit less heavy?

John

TR5 Clutch1.jpg

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John,

I recently changed my clutch assembly. The old B & B was in very good condition after 30k miles but I wanted a lighter pedal action so changed to the Laycock version. (See my earlier thread). However a Koyo bearing was used with the B&B set up and I replaced it as a matter of course with a new Koyo with the Laycock assembly, despite the fact that the Koyo bearing I took out showed no wear at all. Similarly the B&B clutch fingers showed very little wear / witness on the clutch fingers. (See pic). After some research I am convinced that the low wear evident is due to the actuating set up using an adjustable slave push rod and spring which pulls the bearing away from the clutch fingers when not engaged. This allows the bearing to spin freely on the phosphor bronze carrier without touching the fingers of the clutch assembly hence reducing contact wear. This is covered in some detail in Roger Williams books on restoring and improving the TR6. Let me know if you want me to send you a copy of those articles.

Bottom line is that there are too many negative comments about the RHP bearing for there not to be some issues to avoid and I followed the evidence I had with the condition of the 30k mile clutch assembly I took out. I remain convinced too that Jap manufacture remains significantly superior to copy parts made off their western shores.

Hope this helps.

TonyC

6E713A1B-7C39-4F3E-B2A6-A53DA039F8E1.jpeg

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The Koyo bearing is reliable. None of the issues that afflict the standard bearing. Not sure if removing the spring would reduce the chances of the RHP failing.

The flip side is it does wear the clutch fingers.  

I swapped my clutch at the weekend because, after 20k miles and with trips to France and Sweden planned for this year, the nagging doubt about this wear prompted me to change it.

As it turned out minimal marking on the fingers of the Laycock cover and hardly any sign of wear on the Helix plate. So a waste except for finding that the mounting was debonding and the reassurance that the pressure plate wasn’t going to disintegrate. I am not sure my slave cylinder has a spring, certainly very light if it is.

Replaced with a new plate and rebuilt Laycock cover and another Koyo bearing. 

Interestingly many of the specialists (Stag and TR) sell this as their as their uprated bearing at prices varying from £30 other £60. Got mine on EBay from Robsport in his alter ego of Numpty.

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John, I got the Koyo bearing from:-

George Lodge & Sons Ltd
Tel:    01482 329553

Direct:  01482 388487

Registered Office:   80 English Street
                                       HULL
                                       HU3 2DT

In February when I bought it they ordered two from their supplier in error. Might still have it. Contact adam@georgelodge.co.uk

TonyC

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Having now got the engine and gearbox out, I can confirm that its not the RHP bearing itself that is squeeking, its the contact of the bearing with the clutch levers that is making the noise.

I had repacked the bearing with grease, when I had the engine out in August last year.  The bearing turns fine, and the grease is still in there!

One further question, how should the slave cylinder be mounted to the bracket, and where is the bracket mounted, is it on the engine back plate or the gearbox side?

The last slave cylinder I bought and fitted, the mounting flange was only machined on the rear side, not on the front side, looking at the old one I took off (I keep all my old parts) its machined on both sides of the mounting.  The bit I don't really understand, if the slave cylinder is mounted on the engine back plate side the piston in the SC is very  near its full travel, so I did mount the SC on the gearbox side, which put the piston in the middle of its travel, with still room for plate wear and fingers rising. How do others see this?

Is there not a place that we could lock a page with all the details just a one pager of the MC, SC diameters and rod lengths so its easy to find, with perhaps the best cylinder dimensions for the best operation it seems to be spread everywhere and not easy to get too?

John

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Doing some more checks with how the SC should be mounted, I see the clutch lever arm is quite far angled back when it is just in contact with the release bearing.

Should the lever be vertical when it is just touching the clutch?

There could be several discrepancies but am unable to check any other cars systems here.

Could the cross shaft hole be in the wrong place for the fork? the tapered pin is fine had it out and checked, also fork is also pinned to the shaft, or the release sleeve has a wrong dimension.  I now have a measurement from the rear face of the SC mounting bracket to the middle of the pin in the lever of 6 1/4"  does this match with anybody else's?

Could it be a different gearbox?  what should the dimension be from the front face of the casting to the cross shaft centre?

I'm just really trying to identify if the operating lever is in the correct position, as it puts the SC at very near the end of its travel, or am I being too concerned??

Have I now got the SC mounted correctly?

John 

IMG_3817 (2).JPG

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Interesting to note how much wear there is on the clutch covers pictured above.

Here is mine, which was originally installed around 7 years ago, which has probably covered around 40k miles in that time.  This is a 3-piece AP Racing clutch kit, and the associated release bearing.  It was removed to change the clutch plate only at the weekend, which had become saturated in engine oil, after the rear crank main oil seal had said enough is enough after 11 years of service. Release bearing was still nice and quiet.

B & B.jpg

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59 minutes ago, John L said:

Doing some more checks with how the SC should be mounted, I see the clutch lever arm is quite far angled back when it is just in contact with the release bearing.

Should the lever be vertical when it is just touching the clutch?

There could be several discrepancies but am unable to check any other cars systems here.

Could the cross shaft hole be in the wrong place for the fork? the tapered pin is fine had it out and checked, also fork is also pinned to the shaft, or the release sleeve has a wrong dimension.  I now have a measurement from the rear face of the SC mounting bracket to the middle of the pin in the lever of 6 1/4"  does this match with anybody else's?

Could it be a different gearbox?  what should the dimension be from the front face of the casting to the cross shaft centre?

I'm just really trying to identify if the operating lever is in the correct position, as it puts the SC at very near the end of its travel, or am I being too concerned??

Have I now got the SC mounted correctly?

John 

IMG_3817 (2).JPG

That cross shaft looks to have been repaired on the end where the arm goes so all bets are off regarding the angle of the lever Im afraid.

Stuart.

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Hi John,

Your pic shows the correct installation of the slave, ie the mounting plate bolts to the engine side of the bell housing, the slave mounts onto the plate inserted from the gearbox side so that the machined flat surface (rear) of the SC flange mates with the plate.  The push rod locates into the centre hole of the lever.  This is to get the SC piston as close to the operating lever as possible to ensure the 16mm (0.625")of travel that is required to release the clutch driven plate and hence avoid clutch drag.

Your setup does show that the lever may have been re-welded onto the cross shaft which is perfectly OK as long as it was welded in the correct position. I don't believe there are any drawings of the cross shaft/bracket assembly which would show dimensionally the bracket orientation relative to the tapered pin hole in the cross shaft.  Others may prove me wrong, hopefully. I notice from your pic that the push rod is not on the same centre line as the SC cylinder bore. FYI mine was pretty much the same and I concluded that it may have always been this way. If you eyeball it all, you get alignment if the rod is located into the bottom hole of the bracket, but that will fail to give the required movement to allow optimum clutch operation and I'm guessing that Triumph found this out during (late) development and put the other holes in the bracket to counter the problem. It will stress the SC and effect life of that component but one solution may be to renew the seals as a routine rather than waiting for failure. Also FYI my SC failed and I ended up with 3 new cylinders all different and none with a machined flat surface for mounting the correct way onto the mounting plate.

One other interesting fact is that originally the concept was that the clutch assembly would be self adjusting, avoiding a service operation.  However apparently it was later found that once the assembly and all its components started to wear then the magic 16mm movement was lost leading to clutch drag and in some cases inability to disengage the clutch altogether - hence the intro of the adjustable push rod and addition of return spring top allow free play between the push rod and slave. Down side is that you need to make adjustments at routine services, which isn't a big deal really.

I'll send you some supporting info in a pm.

TonyC

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Hi  Tony

Thank you for your comments,   the push rod, I dont have it connected to the MC at the moment, so its just resting on the slave, I need to work out a way to push the cylinder out a bit more and then measure how close it is to the end of the SC, will do that later and give a dimension.

John

Add.......  SC piston is just 0.319" below the end of the slave with the thrust bearing touching the clutch cover. So pressurising would just put the piston just out of the end of the cylinder.

Edited by John L
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Hi John/Tony

Yet to fit my Past Parts reconditioned OEM SC so this is an interesting post.

Is the alignment improved with the original OEM SC? Anyone any pictures of a functioning OEM set up?

If not it seems to be possibly a poor design let go for the expediency of production. I wonder if making a new plate/bracket to better align the SC push rod to the middle lever hole would be worth while to improve longevity and reliability.

Final question around the 16mm ROM what are the reference points for its measurement and is it worth fitting from the get go an adjustable push rod?

Any info gratefully received.

Thanks

Andy

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Andy

Here's a picture of the SC fitted correctly, it does line up correctly, and the bracket is in the correct place.

I talked with Rimmers concerning the SC was not machined on the bleed nipple side of the SC mounting lug, (my original was machined on both sides) they explained that the SC that they get now is for a Land Rover, as they say they cannot get the original anymore, may be true perhaps?

John

 

IMG_3821 (2).JPG

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Does anybody have a long back flywheel, from a CP engine in good condition that could take a measurement for me please?,  

I'm looking for a measurement from the flywheel face, (where the clutch plate runs) to the area/face where the bolts go thu to the crankshaft.  I'm hoping it should be in the region of 25mm hopefully.

Much appreciated 

John

 

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This is from a TR 250 but I believe they share the same flywheel. Measurement is 34.6 mm.

If you looking for the step down from the flywheel face to the mounting face, its 14.7 mm

 

Flywheel 2.jpg

Edited by Kenrow
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On 5/6/2022 at 5:30 PM, John L said:

Andy

Here's a picture of the SC fitted correctly, it does line up correctly, and the bracket is in the correct place.

I talked with Rimmers concerning the SC was not machined on the bleed nipple side of the SC mounting lug, (my original was machined on both sides) they explained that the SC that they get now is for a Land Rover, as they say they cannot get the original anymore, may be true perhaps?

John

 

IMG_3821 (2).JPG

Hi John,

 it would be very easy to machine that mating face flat if you had access to a lathe.

One would think that Rimmers would do this and add a couple of ££ to cover the cost.

 

Roger

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Have you any reason to suspect a flywheel problem? Was the clutch slipping? Have you any reason to think it has been machined before - either to resolve scoring from a worn driven plate's rivets damaging the face or someone has machined the wrong part of the fly in a weight reduction exercise? Other tell tales may be drill marks from balancing.  Apart from the squaling were you having difficulties engaging a gear or slipping? If not then it is likely the basic set up is OK even if the angle of the lever is a bit towards the rear from being re-welded.  A point to note is that with a new clutch the fingers will be relatively forward compared to the same cluch as it wears. Watch as you bolt the cover on the fingers "move" forward as you tighten it.

Your cover being scored by the slave cylinder is essentially unrelated.

The quealing where the release bearing contacts the cover suggests that the bearing isn't rotating at the same rate as the flywheel. To an extent this is normal - when you press the pedal, the bearing makes contact with the fingers of the cover and takes a short time to accellerate up to speed. The Koyo baring takes a tad longer as it is heavier hence a bit of wear is typical but no real quealing.  Your RHP bearing wearing it (the cover) this much and squealing suggests that under load it isn't spinning at the same rate as the flywheel.

 

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28 minutes ago, Andy Moltu said:

  Your RHP bearing wearing it (the cover) this much and squealing suggests that under load it isn't spinning at the same rate as the flywheel.

 

RHP bearings have been known to allow their grease to come out and then run dry.

 

Roger

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If it is possible to pack them with grease after they have been manufactured it does rather suggest that the grease can get out by the same route.

Either the bearing supplied as the "original" is the same in terms of part number only compared to what used to be around and is essentially low quality or something about the working environment (of the bearing) has changed. Clutch facing materials are different from when the cars were manufactured and the bearing specified (no longer contains asbestos) and it may well be that the dust/debris from this contributes to the failure?

Personally I wouldn't fit the RHP and prefer the Koyo as it is such a pain to remove and refit the gearbox.

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Hi Andy,

 about 5/6 years ago Moss were selling a cheap and an expensive RHP bearing -  one at apprx £20 the other nearer £60.

I bought and fitted the £60 item and it has been working ever since.  

The cheap RHP does not mean that it was a fake. All bearing manufacturers (inadvertently) make different grades of quality.

If you pay peanuts etc etc.

 

Roger

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Andy,

I'm trying to work out why the cross shaft outside lever is way back, and the push rod is nearly at the end of the slave cylinder, when in the rest position.  The pin is not broken

So either the cross shaft is wrong or the flywheel is not as thick, which will allow the thrust bearing to contact the cover further forward, thats why I have asked for the thickness of the flywheel.

is you read the Revington article on flywheels mine would appear to be much thinner, hence I asked the question of the distance from the bolts to flywheel face, which Ken very kindly gave as 14.7mm which is similar to mine, which doesn't tie up with the RevingtonTR article.

I'm just trying to find out why the slave piston is so far out, when its mounted in the correct position.

Roger,

As for Rimmers facing off that slave cylinder, I don't think that will happen....... Sell it wrong... customers wont notice.

John

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15 minutes ago, John L said:

Andy,

I'm trying to work out why the cross shaft outside lever is way back, and the push rod is nearly at the end of the slave cylinder, when in the rest position.  The pin is not broken

So either the cross shaft is wrong or the flywheel is not as thick, which will allow the thrust bearing to contact the cover further forward, thats why I have asked for the thickness of the flywheel.

is you read the Revington article on flywheels mine would appear to be much thinner, hence I asked the question of the distance from the bolts to flywheel face, which Ken very kindly gave as 14.7mm which is similar to mine, which doesn't tie up with the RevingtonTR article.

I'm just trying to find out why the slave piston is so far out, when its mounted in the correct position.

Roger,

As for Rimmers facing off that slave cylinder, I don't think that will happen....... Sell it wrong... customers wont notice.

John

:lol::lol:  I would offer to do it myself for free but I think their attitude is " take it or leave it"

 

Roger

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Having just swapped the cluch on mine (and had the same thoughts and self doubts about whether I had assembled it correctly) I don't think your lever is wildly out of place.

As the cluch wears the slave piston will move in a bit, so with a new clutch it is at its maximum.

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Andy,

The slave piston position shown is without pressure from the master cylinder, if that cylinder is meant to move 0.600" it will come out of the cylinder very nearly, the clutch plate has already done in excess of 12,000 miles so is not in a very new state.  So how far inside the slave was your piston, or didn't you check it?

RevingtonTR have been very helpful in identifying that the cross shaft middle hole is not in the right place, just now waiting for the new used shaft to arrive, then I can only confirm which item was a fault.  They said they had seen it before, batch problem with the shafts, the hole is not in the right place compared to the lever, will post some pictures with the fork when it arrives.

Some detail can be seen in magazine 328 April/may last year.

John

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