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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Warning: 1275 release bearings

I have mentioned before the weakness of the type of carbon bearing which is secured by a small rollpin through the side rather than a full interferance fit. The carbon stresses around the pin and eventually cracks, leading to premature failure after only a few thousand miles. The photo shows a bearing with such a pin, circled in red. The plastic cover over the carbon is a feature of these bearings too.

It appears that there are still many of these out there being sold, despite sellers knowing that there is a problem. They appear to have the attitude that it's OK because not many have complained about failure.

If you buy a new bearing, inspect it carefully and don't accept anything with a pin unless you want to repeat the whole exercise next year.


Paul Walbran

Paul,

this is a recurring theme. The attached photo is from a clutch from about 10 years ago - it was stored and not used until 2008. It too only lasted a few thousand miles before failing.
Good advice for anyone needing to replace their clutch.

Jeremy


Jeremy 3

Didn't someone offer a roller bearing conversion for these engines? A far better idea than the carbon bearing in my opinion. If they haven't, then there's some money to be made by designing one.
Clive Reddin

You can certainly get a roller bearing for the MGB. Is there one for the midget?
Mike Howlett

yes, Peter May (item 5.6 in the link below)

http://www.petermayengineering.co.uk/specialistProducts.htm#5.6

Norm
Norm Kerr

Hi Paul,thanks for this timely warning.I'm in the middle of fitting a type9 conversion from MMC in Bimingham.Just checked the release bearing and it is exactly as you describe,plastic cover and roll pin,so the Morris boys haven't got the message.
steve cowling

Just dug out(found) my bearing and I too have the unwelcome version. Bought it from Moss around 18 months ago. Does anyone currently supply the prefered item?
Derek Stewart

Hi, I bought a clutch kit least week from David Manners (J2 M5) and the release bearing doesn't (as far as I can see) have the roll pin as per the photo above.

When I ordered they told me that they didn't have an OE kit but had an alternative.

This turned out to be a Powertune branded kit. Seems to fit ok will let you all know if there are any issues when the car is back on the road (should be this weekend)

Thanks
Mark
Mark Whitmore

Peter May,as always,has the correct kit,and merely raised his eyebrows expressively when I told him of my saga.MMC meanwhile have not heard of the problem,and continue to sell this bearing for Moggies.They do however only supply their roller release bearing for T9 conversions.I asked for the carbon one to mate with my (old) 7.5'' clutch.
steve cowling

OE kits have the correct bearings in them as you would expect.
The Powertune bearings I've had thus far for both B and Midget appear to be OK. They are marketed by County.

MMC's comment is undoubtedly in good faith, as the bearing will typically do up to 10000 miles before collapsing, and it may take some time to get drive far - years perhaps at the rate that some classics are used now. And there may not be as much stress in them if the cars are diven in a less spirited manner than MG's.

There is definitely a problem, however. The number of claims we've had is in double figures and rising, so as you can guess it's been very expensive for us as we have felt obliged to pay out on the replacement labour too. We stopped supplying these as soon as we discovered the problem of course, but in the meantime we'd unknowingly sold quite a few.
Paul Walbran

I've checked a new spare I have from Moss - over 3 years old and it has the pin as well - now going in the bin.

R.
richard boobier

I bought one from Moss about five years ago. I don't know if it had the pin, but the dimensions were all wrong, so I sent it back.

Some suppliers are selling the same bearing, supposedly for 948, 1098 and 1275!
Dave O'Neill 2

Dave,

From your comment "Some suppliers are selling the same bearing, supposedly for 948, 1098 and 1275!" I assume you are saying they arent. For future reference, what are the differences?

Thanks,

Doug
Doug Plumb

The difference is in the distance from the lugs to the face of the carbon bearing.

The 1098 clutch cover is much deeper than the others, so the bearing has much less offset.

Part numbers:-

948 - GRB101
1098 - GRB102
1275 - GRB107
Dave O'Neill 2

Dave, beat me to it!, according to early Moss catalogue:-
-948 13mm depth
-1098 21mm
-1275 24mm.

Jeremy, the damage on the bearing carrier looks as though the arm pivot bolt and bush is shot. I always replace them to remove all the side to side movement, otherwise the bearing gets a nasty sideways shock loading everytime the clutch is engaged.
The spring clips also need to be a snug fit, I've found some very loose 'new' ones.
Kim Dear

The correct type of bearing is available, for the 1275 at least, from Quinton Hazell part no. CC82.
Derek Stewart

My Midget just 'ground' to a halt. Luckily I limped it back to the drive. So engine out tomorrow. Bastard f*cking thing. I REALLY miss the T9 in my Sprite now.

Where do I buy the carbon?

Is there still a problem with 1275 carbon bearings, or has it been fully resolved now?
Lawrence Slater

A call to Hardy Engineering might provide a contact for a reliable source.
Doug Plumb

I gave up and bought a ball bearing conversion from Peter May. So far so good.

Jeremy
Jeremy Tickle

Hi,

The bearing I commented on above disintegrated after less than 1000 (enthusiastic) miles.

I decided not to take the chance again and have gone for a roller bearing from Peter May.

Lets hope this one lasts longer!!

Thanks
Mark
Mark Whitmore

Secret option two... buy a 1500!

Sorry... not helpful! :-D

Malc.
M Le Chevalier

I have a Peter May roller bearing and fitted it several thousand miles (many on enthusiastic track days) ago and so far no problems at all (famous last words #76).
Chris Hasluck

I'd rather not invest in a roller, if carbons are pok now.

This thread was dated March 2011.

Has anyone bought a new carbon recently and can say if they are ok now?

Lawrence Slater

I've been looking at threads on the roller conversion for the 1275 Spridget clutch. It seems it's not all plain sailing on that either.

So doesn't anybody have a good word for carbon release bearings anymore? Can you buy a decent one these days or not?
Lawrence Slater

I use carbon release bearings with the Peter May rally clutch cover, but I've always managed to find NOS parts so can't vouch for current manufacture.
David Smith

I haven't bought a carbon bearing since the incident mentioned previously, in 2011.

I do have a collection of used release bearings, which I deemed too good to discard.

Another reason for seeking out NOS.
Dave O'Neill 2

Groan. If I was keeping the Midget, I'd type9 it.

Well, for circa 15 quid from Sussex then, it looks like I'm going to update the collective on the state of the current carbons.

Just about to go and take the engine out.
Lawrence Slater

Because we heard of the problem with MGBs many moons ago we always physically check what we sell out to make sure it is correct in terms of will it fit, right part and quality as best we can. We have been OK with our Borg and Beck and AP clutch kits which we tend to prefer. The number of times I buy things for myself and they are wrong gets me down at times. I suppose if a business relies on spare parts it is harder to check them. I bet Paul checks what they sell out too!

Peter
Peter Burgess Tuning

Interesting link , shows the difference between 948 / 1098 /1275 release bearings

http://gerardsgarage.com/Garage/Tech/TO_Bearings/tobearings.htm
R Mcknight

A peripheral point: don't try and use a Morris Minor roller bearing. It's too heavy.
Nick and Cherry Scoop

who sells a roller conversion like this then -- in the uk? -- From the link R Mcknight posted of Gerards garage.


Lawrence Slater

Colin Dodds

http://www.spriteparts.com.au/shop/performance.html#Rollerclutchreleasebearing

Rob
Rob aka MG Moneypit

Australia's not much good to me Rob.
Lawrence Slater

Luverly morning for an engine out.


Lawrence Slater

Beautiful ain't it? It did this within 5 miles of 1st making a grinding feel through the pedal. I just made it home.

I found an old but worn carbon in the loft. The carbon is too worn to use, and it's lose in the carrier. So I took it out.

What's to prevent the making of a DIY roller conversion, using my own carrier? All I'd need to do is find the correct sized thrust bearing, and mount/fix it in the carrier wouldn't I?

Anyone ever done/tried that?




Lawrence Slater

Did you check the spigot bearing while you were in there?

My spare crank has a bush.
Dave O'Neill 2

that's been running offcentre so deffo renew the bush in the arm and also the pivot bolt.
David Smith

Worth checking the pivot bearing and the special bolt on the clutch arm, they wear and accelerate carbon bearing wear.
There is a replaceable bush in the arm.

R.
richard boobier

Didn't pull it apart yet. Just took out the engine, took a picture, and went out for the afternoon.

Haven't looked in the crank either. Will check arm and crank bush tomorrow.

Meanwhile, what do you reckon to my home made roller idea? Surely all that's needed is the right size thrust bearing. I'm going to ring SKF on monday as see what they would recommend, assuming the carrier is the right size for an off the shelf bearing.

Question 1.
Does anyone know if the roller conversions available from MM and Peter May etc, use the standard Spridget carrier?

Question 2.
Can anyone tell me the amount a NEW carbon bush extends from the front of the carier?
Lawrence Slater

'Question 2.
Can anyone tell me the amount a NEW carbon bush extends from the front of the carier?'

I have a new boxed QH CC82 carbon thrust (1275) and the carbon protrudes approx 3.6 - 3.8mm from the edge of the cast carrier to face of carbon.

R.
richard boobier

Thanks Richard.

I measured my empty carrier. It's 54.6mm diameter. It's 8.3mm deep.

So add on the 3.8mm of the carbon above the rim, and I'm looking for a bearing of circa 12mm depth x 54/55mm wide.



Lawrence Slater

Should be possible. Nearly 20 years ago my brother-in-law made one up for my MGA. I think it ended up being a top-hat shape because the carrier dia was insufficient for the available bearings, but you can't do that if you're looking for a really slim one. But I do remember he managed a perfect interference fit.

Cost me £56.75, though. In 1998, from Royce Power Transmission of Harlow. Seven items on the invoice - none of which I can read.
Nick and Cherry Scoop

Lawrence,

I don't think you should assume that the iron castings are all exactly the same. Wouldn't it be better to know the distance from the carbon face to the pivot where the carrier meets the fork?

Charley
C R Huff

Lawrence
Looking at a Peter May roller release that I have on the shelf I believe the carrier to be the body of a 948 release bearing.
Straining the old grey cells I seem to recall an article where a roller release was made using a Ford V4 release bearing. I'll keep searching.
Alan
www.maskent.org
Alan Anstead

You could be right there Charley. But my thinking -- perhaps wishfully -- is that there is the same amount of useable carbon above the carrier on them all. And that should tell me how thick I need a bearing for 'my' particular carrier.

Cheers Alan. I haven't got any personal experience of P May rollers. But I see from some threads that they are considered 'top heavy' -- rightly or wrongly. So I'm looking for a low profile type I guess. But anything you can find will be helpful.
Lawrence Slater

Well anyway. I've got an oilite spigot in my Midget crank. So if all '74 RWA Midgets left the factory with a needle roller spigot, then my crank has been swapped. Not that it matters, the oilite is in fine fettle.

No so my clutch fork, and slave push rod, -- as you can see.

The bush in the arm is perfect, so not the cause of the knackered carbon. But I reckon the arm/rod combination might have resulted in the carbon being in heavier contact with the clutch cover than it should have been. Tantamount to riding the pedal.

So chicken and egg. Was the arm bent to match the extended slave rod, or was the rod extended to match the bent arm? If the latter, how the f*ck did someone bend that arm if not on purpose?

I'll straighten it tomorrow and make the rod the correct length again. I've also got to take the slave off, and find a circlip to hold the piston in, -- it's missing.



Lawrence Slater

If its the later 1275 slave, I don't think they have a circlip. Mine doesn't and its a genuine Lockheed one. The earlier slaves do.
Bob Beaumont

Lawrence,

The bent fork arm is a classic case of over pressuring by extending a pushrod instead of sorting a clutch problem at source.
The hydraulics just bend the arm - it seems to bend before it wrecks the p/p but the trust is also taking additional load.

I have arms in a similar shape (well I think yours is very slightly more bent !).

R.
richard boobier

That's one of the finest looking pushrods I've ever seen ;o)
Dave O'Neill 2

Hi Bob.
Without the rod and arm to hold it in, my piston gets pushed out of the bore by the spring. Does yours?

Can the arm be bent by the hydraulics? Amazing, it feels pretty strong, and the arm from my Sprite before I went T9 is still straight, and that's served at least 25 years.

Yup. The rod's a lulu. It's also slightly bent too. lol.
Lawrence Slater

Hi Lawrence, I have a replacement(Powertune?) Slave which let the spring push the rod out resulting in puddle on the garage floor!

Cable ties sorted out a temporary hold on it

Thanks
Mark
Mark Whitmore

Hi Lawrence

Yes it does but the rubber boot seems to hold it in. If the pushrod is not 'modified' and with the right release bearing the piston is well down the bore so it doesn't matter. There is also no groove in my slave for the circlip anyway!
Bob Beaumont

OK, cheers Bob, Mark. No doubt saves money making them.
Lawrence Slater

Lawrence.
I used a standard 1098 clutch cover and carbon release with an Avenger driven plate for my T9, using a MMC bellhousing.
What I didn't know was that one of the holes in the bellhousing for the pivot bracket was drilled slightly out of alignment making the release bearing engage off centre, which eventually destroyed it. I still didn't notice the misaligned hole and thought it was just a bad carbon thrust.
I bought a 1098 roller bearing from Colin Dodd in Aus as no one in the UK does 1098 ones and fitted it only for the off centre fork to vibrate the bearing out of the carrier and knacker the freshly re-bushed pivot.
When I removed it I found that the bearing wasn't a proper interference fit in the carrier and had been secured with a thin sleeve and bearing seal. Also, the inner race was bottoming out on the carrier which had been the source of the slight squealing sound I had heard on depressing the pedal.
Because of the mis-aligned pivot hole there was no point in fitting any type of release bearing that utilised the fork, so I was forced to go concentric, which has worked very well. I wish I'd done it in the first place.

I gave my Colin Dodd one to Les Robinson and he has re-engineered it. He got a new bearing which was a good press fit in his 948 carrier (mk2 Sprite)and used the Dodd centre contact part. He also counter bored the carrier under the inner race to provide clearance between the inner race and carrier.
He did say that the carrier that I gave him and his carrier had slightly different IDs.
His car is not mobile at the moment due to the diff being rebuilt, so I can't tell you if it is successful or not, but knowing Les, it will have been done properly so should be OK.
Hope this helps.

Bernie.
Bernie Higginson

Hi bernie.
I think you might have been a bit peeved that the bearing was only 'glued' in, esp for that money.

What number was the original roller bearing from Colin?

Do you happen to know what replacement bearing Les used?

My research has so far led to a 55x30x13 7006 angular contact bearing. Good for axial and radial loads. The sealed version of that is 70062RS. circa 20 quid.

My carrier is 54.5mm. So a little machining should result in a good tight press fit. But I wondner if a couple of grub screws in loctite in addition, might ensure that.
Lawrence Slater

But for now, I need the Midget back on the road and can't wait whilst I faff around sourcing the roller bearing and making it fit the carrier. So I've ordered a carbon from Sussex.

Then I'll get the roller, make a conversion, and let people know if it works ok in principle. I can't see why it won't.

How much Cost wise?
1). You need a good carrier, so that could involve the purchase of a sacrificial carbon for some.
2). The carrier is going to need machining to take a 55mm o/d bearing as a press fit.
3). The cost of the bearing.

Likley to cost more than the Peter May version I think. I'd like to know what bearing is used in that.
Lawrence Slater

Hi
I used the Colin Dodd spec bearing but fitted a new one that I got locally.
It is a deep groove ball 61907 greased and sealed -35mm x 55mm x 10mm
The OD was a nice tight press fit into the standard 948 thrust bearing body without any mods.
It is important though to machine a recess in the housing to give clearance to the bearing inner race.
An angular contact bearing is probably a better choice although the deep groove ball should be good for axial force in excess of 800 lbf. Not sure what the actual force is at the thrust bearing though!
Les
Les Robinson

Hi Les,
I was told the deep groove risked the inner being pushed out of the outer, but if you haven't had a problem, then a 6006 2RS would do the job and not need the extra machining to the carrier. 55x30x13. 10 Quid inc Vat.

I forgot to add to my list the top hat to act as the bearing face.

Somewhere out there, there must be an off the shelf automotive clutch release bearing of the right dimensions, that could be removed from it's carrier and pressed into the Spridget carrier.


Edit. less than 3 quid free postage.
http://www.ebay.co.uk/itm/6000-2RS-to-6006-2RS-Rubber-Sealed-Bearings-Choose-Size-6000RS-6006RS-/131127383752?pt=LH_DefaultDomain_3&var=&hash=item1e87cd16c8
Lawrence Slater

Moss sell a roller release for the MGB for £29.95

How come nobody does the same thing for the Spridget at that price?
Lawrence Slater

Lawrence
I haven't run mine yet so cant guarantee it will be ok!!
Generally a deep groove ball bearing will take a pure axial load to a value of up to 0.5 of its static load rating.
Angular contact is probably the better choice - just make sure you fit it the correct way round!!
Which ever bearing you get go for a known make ie SKF, KOYO, NSK etc. Dont just get the cheapest as its likely to be cr*p.
Les
Les Robinson

Here's a radical thought.

If I could find a carbon graphite pad/block of sufficient dimension and the correct hardness grade that used to be used, I could carve it to shape and fix it in the carrier. lol.
Lawrence Slater

Lawrence,

How thick is the graphite you would need and diameter, I have some of this http://www.graphitestore.com/itemDetails.asp?item_id=531&prd_id=27&cat_id=22&curPage=1
David Billington

Hi David,

Earlier Richard said that a new QH brand carbon release bearing he has, has appx 3.8mm of carbon above the carrier. I've measure the internal depth of the empty carrier I have, at 8.3mm. So I reckon I'm looking for a thickness of circa 12/13mm.

I spent 1/2 hr this pm scanning the web looking for UK suppliers, but found none. Plenty in the US though.
Lawrence Slater

Lawrence,

I had a quick look on ebay and there was a least one carbon insert for a release bearing for sale and plenty of release bearings. Any idea of what is used to fix the insert in place.

Regarding graphite suppliers in the UK a company called Graphite Trading used to sell offcuts but don't any longer but when I asked they suggested contacting Coidan Graphite Products at Kirk Hammerton near York http://www.coidan.com/. There are other graphite suppliers in the UK, I've dealt with one, but found it easier to order from GrahiteStore in the US.
David Billington

Nope no idea. Modern carriers seem to be a molded plastic of some kind, into which you clip/clamp the release bearing assembly that comes complete with the bearing face.

But look what I found here.
http://tinyurl.com/olkhhxj
0086parts.com/auto/product/clutchreleasebearing.pdf

It's a PDF catalogue with all the car makers clutch release bearings -- WITH DIMENSIONS.

But who are TEMCO?


Lawrence Slater

This is easier to read. But I'm having trouble relating those dimension keys to the bearings in the pictures.

Anybody?

Also, PAYKAN, hit the buffers and no longer make cars. Iran you know. lol.


Lawrence Slater

Aha. TEMCO.

http://www.0086part.com/auto/index.html
ADD: Fl 4, New Linli Plaza
No.80, Shangjiang Rd.
Wenzhou, 325000
China
Tel: 0086-577-88802125
Fax: 0086-577-88802126
Email: marketing@0086parts.com
Web: www.0086parts.com
Lawrence Slater

Because I need the Midget back on the road, I ordered a 1275 carbon release from Sussex. -- Worry about a roller later.

This is what arrived. The box says 1275 GRB107.

It's identical to the Moss product, -- http://www.moss-europe.co.uk/release-bearing-clutch.html -- complete with the roll pin in one side, and the same casting number on the back. 3502.

I reckon it's a 1098 carbon release bearing.

Here's a picture of my 30 year old 1275 carbon release (carbon missing), next to the one sussex sent me.

The one I took out of my 1275 Midget, is exactly the same as my 30 year old carrier.

Sussex tell me it's the correct one, and has been sold for 20 years as the correct one for a 1275.

Who's right? Am I wrong?



Lawrence Slater

You're right, and they're taking and selling sh1te.
Here's the best of my 1275 'too good to throw out' selection.


David Smith

Lawrence,

I have both bearings (the one from Moss with 3502 on the back - boxed as GRB107 complete with pinned carbon) and a QH CC82 and they are virtually the same dim from rear of pivot to front of carbon.

However the outer dims are a little different and the other problem is the width between the pivots to fit within the arm yokes - the CC82 is 63.8mm, the Moss 3502 65.4mm - so not sure it will fit without filing either the bearing or the arm (havn't tried).

I will not use the pinned bearings as too many failures seem to have been reported.

Are there no general auto suppliers with QH stock ?
Heritage market clutches I seem to remember who's do they supply ?

This is another wheel bearing issue !!!

R.
richard boobier

But don't forget that the QH CC82 castings are themselves pattern parts. I believe the OEMs are the AP Borg & Beck ones, with casting number 75509.
David Smith

Ahh I have a used one with 75509061 on it - didn't know who made it.
However there seems little difference to the QH one.

R.
richard boobier

My two old ones are CC82, and are both as in my picture of a 1275 carrier below, AND, exactly the same as David's.

Richard, -- " -- from rear of pivot to front of carbon."

Yes, mine too. There is a lot of carbon ABOVE the rim of the carrier on the 3502 casting. BUT the top of pin to rear of casting on the CC82 is 4mm, whereas on the 3502 casting, the tops of the pins are level with the rear of the carrier. The offset is wrong.

BMC made the offset for a reason, reducing it and adding more carbon to compensate doesn't sound right to me. If it is right, then why did BMC go to the bother of making 3 different castings with 3 different offsets for the carriers? 948, 1098, 1275.
Lawrence Slater

I should add. I went to my local auto shop to see if I could order a QH or Firstline or Borg and beck release bearing.

But, you can only buy the CORRECT one in a complete clutch kit. 3 parts. Cover, driven plate, and release bearing. You can no longer buy the bits separately, unless it's old stock.

I spoke with amnother supplier today on the phone, and he measured the BORG and BECK kit release bearing. The Borg/beck one is a correct 1275 carrier casting. But you can't buy it on it's own.

The only 1275 carbon release you can get now appears to be a 1098 version. Sold AS, a 1275 one. Moss and Sussex. Unless you can find NOS.

However. Sussex tell me they sell plenty of the 3502 with the roll pin, na dhave no problems. And the chap there with a Sprite, has one in his car, circa 8000 miles and still ok.

So maybe it's ok?
Lawrence Slater

Borg and beck kit number is HK9632.
Lawrence Slater

full circle Lawrence; that's why people bodge the pushrods to make them longer.
David Smith

I agree Lawrence the part is not as it should be - I do not think that amount of carbon is good and as I noted the width is incorrect on the one I have.The pin fixing also appears another part of the problem.

As to is it O.K - well Paul noted above 'There is definitely a problem, however. The number of claims we've had is in double figures and rising'

R.
richard boobier

I had all this last year when I changed my clutch, I put in the bearing supplied with the kit (the clutch was genuine old B&Beck but the bearing turned out to be from someone else). The updshot was I couldn't get the clutch to throw out properly.I heated the arm and bent it until the clutch worked as a temporary bodge. I got hold of an original bearing and as you say lawrence there was a difference. I put the genuine one in, with a replacement straight arm and all was well. l did compare it with an old NOS QH one and there was no difference. Its just another example of poor quality aftermarket parts.
Bob Beaumont

The odd thing is that my Midget had an extended rod and a bent arm. I straightened the arm today, heat and hammer, and I just can't see how it bent without heat. I also corrected the rod length.

Maybe at one point, my Midget had the wrong bearing, so someone lengthened the rod. Then, it got a new correct bearing, so someone bent the arm. Or maybe the other way around.

But now I have a straight arm, and the correct rod length, but the wrong bearing again.

Roll pin aside, the bearing actually looks pretty well made, and there's a lot of carbon there. When I aksed sussex about the 1098 bearing, he said it was shallower than the 1275 one, and he doesn't keep the 948 version. So both the 1098 is ok, but you can't get a 1275 one.

It sounds to me like the people who make these, other than those who supply the OE's don't know the original spec. But that doesn't excuse the retailers who've been in this biz for yonks, and should know the specs.
Lawrence Slater

So back again to making my own roller release conversion I think.

Now as it happens, I also bought a spare clutch kit for my Sprite T9 g/box conversion. It arrived today. It's a 1.6 Ford Sierra 7.5" clutch. It's mated to the Burton(TITAN) concentric slave, and that utilises an SKF roller bearing, which slides over the end.

And as it further happens, the standard Ford Sierra clutch release bearing that comes in the kit, is essentially the same as the Burton bearing, BUT, it mounts on a carrier to fit the Sierra clutch release arm.

And guess what?

The outside diameter of the Sierra roller bearing, is the perfect size to mate against the flat pressure pad of the 1275 Midget clutch cover.

And guess what else?

The Ford Sierra roller bearing carrier, is just the right size to fit between the fork of the Midget clutch release arm.

So I'm going to make a carrier from steel plate, with the right size hole in it to take the Ford Sierra carrier assembly. I'll put the same size pins on each side of my new plate carrier, as are on the Midget cast carrier, so it will fit the Midget release arm fork. But I'll mount the pins without any offset at all, as the Ford Sierra bearing assembly is quite deep. Mounting the pins without an offset, will bring the ford roller bearing face to just the right height.

But I have a problem. Does anyone know what the clips look like that hold the ford Sierra carrier to it's release arm? Does anyone happen to have a Type 9 gearbox clutch release arm with a bearing carrier and clips?
Lawrence Slater

Lawrence,

See images for a type 9 release arm with release bearing fitted.


David Billington

Image of rear, carrier that slides on the guide tube is plastic and has steel clips inserted that have small barbs that prevent the release bearing coming free once pressed in place, you need to gently prise them to get the release bearing out.

IIRC Ford have used that style of carrier for decades on various gearboxes but not all were plastic or had clips. I modded one years ago and found it to be sintered iron or steel and oil impregnated.


David Billington

Thanks David. I got a T9 release arm with one of my spare boxes, and threw it out. lol.

Do you have a picture of the steel clips? They didn't come with my bearing.
Lawrence Slater

Lawrence,

Image of the release bearing and clip. I'm surprised if you have a similar release bearing that the carrier didn't come with the clips.


David Billington

Yup, that's identical David, and the clips are missing.

I'll get on to Borg and Beck
Lawrence Slater

There's a carbon release on Ebay. £29.73+ £4.98 postage. £29.73 Normally £34.98 save £5.25 (15% OFF*)

Seller says it's for:
AUSTIN A40 FARINA- MK2 1962-1968
AUSTIN HEALEY SPRITE - MK2&MK3&MK4-1098cc&1275cc 1962-1971
MG MIDGET-MK1&MK2&MK3- 1098cc&1275cc 1962 - 1974
MORRIS MINOR 1000-1098cc 1962-1971

http://www.ebay.co.uk/itm/MG-MIDGET-MORRIS-MINOR-AUSTIN-A40-CARBON-CLUTCH-RELEASE-THRUST-BEARING-/111384158110?pt=LH_DefaultDomain_3&hash=item19ef035f9e

Seller says it's a CC82, but I can't quite see that from the picture. So I sent him a message, with a progile picture of my CC82(1275) casting, asking for a clear picture of the profile of his, so I could see the lug offset.

Seller replied:
"Hi,
No as the item is away in storage, it is the same style as the one in your photo however,
Regards,
Adrian"

So I sent him another message explaining why I'd like to see the profile. He hasn't replied yet and the discount offer ends in 1 day.

So if you're thinking of buying it, make sure you know what you're buying.


Lawrence Slater

Thanks Lawrence. It doesn't look from the photo the same as my CC82 casting which is new and comes in a QH box. (Its exactly the same as the original borg and beck one) The numbers on mine are very clear and there are no circular ridges. I have another one that does look similar to the one on Ebay but it has a different lug offset and could be from a 1098
Bob Beaumont

Cheers Bob. I'm in touch with B&B(Firstline now), to get some definitive info about what comes in their kits now.


Hi David.

I got a reply from B&B about my Sierra baering and carrier, and the type I've got, has an integral molded plastic clip. But I think I prefer the type you have, with a metal clip. although the plastic seems to be very strong, I don't know how good it would be with my version of a release arm to hold it.

Can you show me how those metal clips retain the carrier on the arm that you have?
Lawrence Slater

Lawrence,

When you push the release bearing into place in the arm the little tabs in the clips catch behind the lugs on the arm preventing it from coming out.
David Billington

Ah right got you David. So they've made the tabs integral in the moulded plastic on the newer versions. Wonder which lasts longer?

But anyway, now I know, I'll knock up a but of plate and have a go.

The seller on the ebay link I gave below, has replied again. "The centre of the pivot pins to the front working face is 20mm, --"

So he's measured it, but seems reluctant to give me a pic of the side view. I'm guessing it's a 1098 carrier, and has the shorter legs.
Lawrence Slater

See here, I just took this off a Morris Minor gearbox (the arm has an eye not a clevis). Note the bearing - look familiar?


David Smith

Here's a cloe-up and the distance from pivot centre to front face of carbon is 20mm. (the dimension for 1275 Midget is 25mm). So another load of rubbish from an ebay seller. Caveat emptor.


David Smith

And he's just uploaded a picture confirming that David.

It may well be a NOS item, grb102, but it's not a grb107 for 1275.

Actually I'm guessing he didn't know. But he does now, and I've suggested that he might like to remove the reference to 1275.


Lawrence Slater

he's a good seller, he's updated the description too :-)
Looking at revisions I see he's had it on sale since last June! Hardly surprising at that price...
David Smith

Yup, he just messaged me to tell he he'd done that. Fair play to him. Hmm very expensive, but for an original, maybe that's the price now. It's going like FWBs.

Going back to my earlier picture of the empty worn carrier in my gearbox, Posted 07 March 2015 at 18:32:59 -- It appeared at first that the arm bush must be worn, to account for the uneven wear.

But actually it was 2 different causes.

1). The arm retaining bolt was too loose. This allowed the arm to fall to one side more than the other.

2). As the carbon wore away, the arm travelled further along the arc. This causes the top of the carbon bearing to fall below the top of the thrust pad on the clutch cover. Eventually the carbon wore down so far that i was metal to metal. The top of the carrier wore because the arm was travelling too far, and the side because the arm bolt was loose, allowing the arm to flop down to one side.

And it was all exacerbated by having a push rod 3.25 inches long.

The bearing sold by Suxxex, Moss, etc, ignoring the roll pin, will work ok for a while. The carbon is very thick, and pretty well makes up for the shorter legs. Hence it keeps the carrier centered about the 1st motion shaft, and thus in contact with the whole of the thrust pad.

However, when the carbon bearing wears sufficiently, the arm will travel further along the arc, the top of the carbon will fall below the top of the thrust pad on the clutch cover, and I reckon that's what starts the rapid disintegration of the carbon.
Lawrence Slater

Not much progress getting the RWA midget back on the road. I'm now bogged down investigating DIY conversion methods to roller release. I'm waiting for a Ford Transit release arm to arrive in the post. Cheap on ebay. Then I'll make it fit the 1275 clutch fork.

I put this in Rob's T9 clutch release thread but really it belongs here too I reckon, since it's all related.

Curly fingers flat bearing face, vs flat fingers rounded bearing face. And, thrust pad clutch cover, carbon bearing. WHY?

When the bearing is pushed forwards, the fingers are moved inwards away from the bearing. If both surfaces were flat you'd get square edges in contact with eachother. So one surface gets rounded off to begin with. And I suppose with the greater area of the thrust pad, a softer carbon is ideal -- except for modern traffic conditions, where there is far more clutch work, and it's better to have a roller that lasts longer.

PRELOAD.
You need preload on the release bearing. Not enough to cause the clutch to partially dissengage/slip, but enough to stop the fingers and bearing faces from wearing eachother out, each time they are brought together. The bearing has inertia. If there's a gap between the bearing and the fingers, each time the pedal is pressed, the bearing face is brought into contact with the fingers, and has to begin to rotate. Initially it would be static, and wear would occur until it was rotating, just like the tyres on landing a plane, and there might well be an audible squeal too.

So you hold the bearing in constant light contact with the fingers. Too little force, and the bearing won't rotate, and both surfaces will wear, and it will squeal all the time, until the clutch pedal is pressed. Too much force and you know the result, clutch slip.

But I don't quite get why a carbon pad is in constant light contact. Maybe because the sudden contact from a gap, is simply to much mechanical stress, and it's better to have a continous light contact, even though that does wear the carbon a little.

Now I'm wondering if a FLAT roller bearing face, against the FLAT metal thrust pad on a standard 1275/1098 clutch cover will work?

I'm about to try that out. -- When my Transit arm arrives that is.

Lawrence Slater

"But I don't quite get why a carbon pad is in constant light contact."
Is it? if so, I never knew that.
If the pedal movement is say 3 inches, and the clutch bite all happens in the middle inch, what happens in the bottom inch and more importantly in the top inch? Surely the first inch of pedal movement is taking up the slack, i.e. closing the gap between the carbon and the thrust plate? Happy to be proven wrong!
David Smith

Hi David,
I was surprised too. I've got my engine out on the garage floor, and my spare ribcase bolted onto it's ar*e end. No hydraulics of course, but the carbon is held against the clutch cover.

Huh? Oh yes I realised, it would be wouldn't it. Because there is quite a firm spring in the slave cylinder pushing on the piston, which is pushing on the rod, which is pushing the release arm fork/bearing onto the clutch cover.

I hadn't appreciated it before, because before I changed to a T9 g/box, my then external 1275 slave cylinder, had a circlip in the end of the bore.

But my rwa 73 midget, doesn't have the circlip, and when I took the cotter out of the release arm and removed the rod and rubber cover from the slave, the piston popped out, pushed by the spring.
Lawrence Slater

Good lord,

Yes the peter may bearing is a bit front heavy as you have stated...but my understanding also well inside of the spec range

I dont think ive ever heard of anyone being disapointed using the peter may roller bearing I cant imagine there being an issue

Id be more tempted to go peter may and if there is an issue work with his in house engineering staff to find the solution then to start from scratch and reengineer the entire concept

Worse case senerio if peter my says to bug off is go the direction of the consentric slave and be done with this whole fiasco

Prop
Prop and the Blackhole Midget

Hi Prop.
I've got an unused new roller bearing and carrier. If I can use it to convert to roller, why not? See my earlier post 10 March 2015 at 22:02:06 UK time for the back story that you've obviously not read.

Also, look in the archives regarding posts by some people, describing the problems with the conversion by Peter May.

But even if the PM one is good, my roller is essentially free, the conversion will cost less than 10 quid, and it's an interesting pastime, --- don't you think?
Lawrence Slater

Lawrence
Have a look at
Omniautos.force9.co.uk
It shows a roller race thrust made from Cortina parts.
Hope it helps.
Alan
Alan Anstead

Okay lawerance

Your correct, I just skimmed over the threads, but ill go back and read up in more detail

But I just dont think this perticular company ??? (Or childs home work project) and part is the answer your looking for

Prop
Prop and the Blackhole Midget

Thank Alan, I'll have a look.

Prop. You may be right. I was just googling, looking for auto clutch release bearings and found the TEMCO catalogue, which appears to contain just about all of them, and that one in particular caught my eye because it's the same type Sprigets use with the A series engine.

Ideally though, a decent carbon would remove the need.
Lawrence Slater

Very good site that Alan, great ideas about the roller. Wish I knew about that before. I might well incorporate some of that into my diy, but as I've already got a sierra roller bearing, I'll alter it to suit.

And guess what? As it happens, I'd already made a remote bleed almost exactly as you describe, except I haven't slotted the fixing lug, because I haven't decided on the final loaction. I'll probably make a 2nd longer lug with a slot, and attach that to my existing lug with a nut/bolt. But whatever, it sure makes bleeding a doddle. And there was/is, no way I intend EVER, to get my head/shoulders inside my footwell again, just to bleed the pissing clutch. lol.



Lawrence Slater

PS Alan. I'm assuming you had something to do with the writing on the Omni site?
Lawrence Slater

Lawrence
The site has nothing to do with me.
I had a very old article on making a roller bearing using what I thought was a V4 roller. Searched hi and low in doors and in the garage. Gave in and tried www and found the Omni site which may or may not be what I was trying to recall in the first place.
Alfred Zheimer.
Alan Anstead

Omniautos is Nick Handford, IIRC he does appear on the BBS occasionally. I recall he did one of those conversions in the late 1980s.
David Billington

Ah well, it's good all the same.
Lawrence Slater

Your right David Billington. In the other thread you mentioned how hard the Ford Transit clutch release arm was likely to be. I can confirm that it is one bloody hard piece of metal. Too hard for me to cut and knock into the shape I wanted.

So I just used it as a kind of pattern, to go from here, ---- to --- see next post ---


Lawrence Slater

To here.

Next job is to weld the studs on the sides, and bung it in the release fork.


Lawrence Slater

Will it work or won't it?

With a bit of luck if the rain holds off, I'll find out tomorrow,


Lawrence Slater

Lawerwnce

It looks great, very well put togather... I cant tell which is real and which is the memorex.

Prop
Prop and the Blackhole Midget

Hah. :). They're both fake. lol.
Lawrence Slater

Raining on and off today so I didn't get the engine in.

But I did mount the roller and release arm onto my spare g/box, and hung that off the engine for a manual test, to see if it would break when I depressed the clutch with a lever on the end of release arm.

I'm pleased to say, it didn't break. The roller release lines up nicely and covers the thrust pad evenly. And with the spring pressure from the slave cylinder providing the preload to hold the release bearing against the thrust pad on the clutch cover, the bearing revolves as the engine turns.

Bit of a shaky light in this video. I was holding the torch in my right hand, whilst turning the engine with a rachet and socket with my left hand.

This is a view looking down into the bellhousing through the top inspection hole.

http://vid1208.photobucket.com/albums/cc362/slaterlp/1275%20clutch%20roller%20release/Movie_zpswcbvnznf.mp4


Lawrence Slater

I'm having a problem making my video accessible.

Photobucket keeps telling me I've removed it, but I haven't, it's there.
Lawrence Slater

Try this.
http://tinyurl.com/kv2jw68

Yup, that works.
Lawrence Slater

UPDATE.

I can confirm that according to a B&B senior clutch product engineer, the release bearing sold in the B&B kitHK9632, is GRB107 made to the correct OE spec.

And the carbon is an interference fit in the carrier.

So at least if you buy a BB kit, you get the right bearing.

And as the Sierra kit I bought was BB branded, but VALEO made, I suspect that you 'may' be able to order a GRB107 of the correct spec from from the Valeo distributors. -- *Maybe*. Euro carparts? perhaps?


Lawrence Slater

I can report that my diy Ford Sierra roller release is working perfectly.

So for anyone who fancies it, one way of doing it is that way I did it

4mm plate steel, and a ford sierra roller release. You can but the roller release for less than 15 quid on ebay, and even as little as 5 quid here. http://www.ebay.co.uk/itm/Ford-Sierra-Cortina-Capri-Escort-Clutch-Release-Bearing-31B21-/370991515097?pt=LH_DefaultDomain_3&hash=item5660d145d9

One thing though, whilst the roller release is fine, either I've got air trapped in the system, or something else is going on.

My diy roller bearing is longer in the carrier than the standard, at 34mm from the centre of the lug. My pushrod is still longer than standard, such that with the bearing hard against the thrust pad, the rod is pushed further into the slave cylinder than it would be with a standard lengh rod. So there should be plenty of throw. And yet, rather than overthrow, it's underthrowing. Pedal hits the floor in order to declutch.

No air in the slave, but maybe there's air trapped in the master. Or, it could be something to do with why my slave rod was 3.25" before I cut it down to standard size.

Are there different lengths of push rods in the master cylinders? Is mine too short?

Poxy Midget. I knew I should have scrapped it and sold the spares.
Lawrence Slater

Well having got more air out of the system -- seems to have been trapped in the master, not the slave -- I've got a better pedal.

Anyway, the roller is working very well. So I'll hack it around for a few weeks, and then change to the Sussex carbon and see how long that lasts.
Lawrence Slater

Just to note what richard said, and I can confirm about the Sussex and Moss carbons Part 3502.

"However the outer dims are a little different and the other problem is the width between the pivots to fit within the arm yokes - the CC82 is 63.8mm, the Moss 3502 65.4mm - so not sure it will fit without filing either the bearing or the arm (havn't tried)."

It doesn't fit without either opening up the fork, or filing the carrier.

As you can see below in the GRB107 drawing, the correct spec is 64mm for a GRB107(CC82).

I opened up my fork a little to make it fit, but you have to do it evenly both sides to make sure the carrier remains central.






Lawrence Slater

This thread was discussed between 10/03/2011 and 31/03/2015

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.