WARNING…BE CAREFUL!!

[Paul bow]

Another point worth revisiting is that the old bearings like old red oxide paint was full of goodies not allowed today. Mostly containing lead a nice lubricating non abrasive substance.
I don’t know for sure but I bet the Original carbon bearings contained such substances mixed in to that bearing which back then would have out lived the engine.
So manufactured parts today that copy that design of old but with substituted ingredients maybe where this has failed, or as i have mentioned could it be I’ve just been unfortunate enough to get a rogue item.
This broke up in chunks, I believe there were hairline fissures from the outset within the carbon bearing itself ..if you look back at the old pics at the beginning of this post I’ve marked it out in yellow, these were not visible obviously when it went in but as pressure was applied by the depression of the clutch so the splits formed and subsequently failed.

[Allrand]

yes I was waiting for this response.

I raised the question as a possibility. I don't know how these parts are made, but presumably some kind of carbon powder glued together with a binder and compressed under pressure. Failure of the binder, contamination, insufficient quantity, or insufficiently compressed, would lead to failure. Variations can occur in most mass production processes, so I doubt that you'll ever find the real cause.

[Paul bow]

Allrand.. I think you are probably on the money with that, I refer to GT joeys comment about AP being really the best bet as it’s a complete upgrade with clutch cover plates and roller release (Rob beeres item is the same, a complete upgrade), this surely with an item that is a real problem if it fails is a no brainer..
even if complete originality is to be followed, unless you can find a new old stock item your using an imposter, so why not use one that does the job right!, as apposed to one that looks similar but is made of different materials being used to do the same job as their predecessors but possibly badly.

Look let’s give credit here, SNG are looking into it, they prob sell 10++ of these a week I don’t know. It has been an issue in the past and maybe there’s more to come out of the woodwork, who knows .. I’m sure I will have an answer soon enough..
It would be helpful for anyone who has bought a BB clutch in the last 6 months fitted has had success or failure might help to nail down a potential flaw. Save fellow owners from a similar fate or indeed give piece of mind.

[zigzagsky]

I had a similar issue with an AP clutch from SNG back in 2019. Failed after 30 miles although this was due to the bearing face on the clutch cover where the release bearing presses becoming detached.

Turned out there was a bad batch from AP. So even AP have their issues….

[Paul bow]

Zigzasky.. that’s a proper disappointment, there you are believing the extra was going to get you the better clutch and even more so that AP do the roller type bearing without that plate on the cover. They sell both types for the e type.
I think that the roller bearing type system has less chance of failure, no break up of the carbon and no risk of the plate falling off, wouldn’t say I’m an expert in the issue but certainly learning fast!
What did you replace it with in the end?

[mgcjag]

Worth looking here re roller bearings.....Steve viewtopic.php?f=3&t=18128&p=147380&hili ... ng#p147380

[Paul bow]

Steve although the e type bearing swings via the fork motion the pivot action of the bearing in the said fork (held in with those funny clips) eliminates that motion as soon as contact is made on the plate.. if it didn’t you’d have terrible wear on one side..that’s my take on it anyhow

[Tom W]

That’s not the issue.

Because the E-type clutch fork pivots and the release bearing end moved through an arc, the release bearing is only concentric with the clutch at a maximum of two points throughout the clutch travel. This isn’t a problem with a carbon release bearing. However, with the roller bearing, it forces the clutch and release bearing to rotate about different centres when they should be rotating as one with no relative movement between them.

Cars designed to use roller release bearings have a different design of clutch fork where the bearing is held concentric with the clutch and isn’t constrained to move through the same arc as the clutch fork. Look at a Series Land Rover clutch for an example.

More modern cars use a concentric hydraulic release bearing.

[chrisfell]

My release bearing was in three parts when it eventually came out. I didn't fit it, that was done may years before I owned the car ( I bought it in 2003). I replaced the bearing because it had also worn down to its carrier.

[Paul bow]

Thanks Tom.. understand that makes perfect sense , appreciated .
Interesting though that the majority of the race clutch’s available from the usual outlets use roller bearings, which you would think certainly have a harder time than the road going equivalent of a carbon item. I know Rob Beeres engines are certainly fitted with them, I’ve one on my bench at the moment. I suppose it boils down to choice, and weighing up potential risk.

[mgcjag]

Hi Paul...note what i said in a previous post...one resto company i know has stopped useing them due to failures....i would ring around a few of the major companies if i were you befor committing to fitting a roller bearing......Its an interesting discussion and adds weight to paying for a clutch to be installed rather than a diy job......a failure would be covered by the installer..Steve

[Jack the lad]

Many years ago when I ran a repair garage, I remember seeing a guarantee printed in the fitting instructions from one of the major clutch suppliers,(sorry cannot remember which company) which stated that they were so confident in the quality of their products that they would pay for the fitting of the new unit if it failed within 6 months of installation. Does anyone else remember this, or better still availed themselves of it?

[Paul bow]

Jack the lad… A guarantee omg that’s wot you call old school certainly won’t see anything like that today !

Steve…
it’s an interesting point you raise, before deciding on what to do next with the BB bearing failing I contacted Pearson racing to see what they used, majority of there engines are roller bearings, Rob Beere (who I buy everything from where possible) certainly use roller bearings, and speaking to Dennis welsh motorsport they said that they sell a lot more roller types than graphite.
However, the general consensus that I got was that the graphite bearing is an excellent design BUT you cannot rely on the quality, they as I’ve said before are not made with the same materials as years gone by, simply not allowed today, that’s the issue nothing more, it’s all about the quality without that its doomed to fail.
It doesn’t matter if you get a dodgy rocker switch, easy, swap it out in a minute different story if it’s in the guts of the engine.

Ok certainly you’ll pay more for your items from a marked specialist, but when it comes to engines/diffs/gearbox’s for me it’s a no brainer, I only want to do it once, which is why I’m banging my head on the wall as to why I didn’t fit a high quality clutch, and the reason for that being I’d fitted them before without issue. Unlucky this time..

One point noting is that the roller bearing requires you to place a simple limiter on the pedal travel, otherwise this can cause dire problems.. be interesting to here the views from your restoration man who had problems, I’m no expert on this issue by any means there’s a huge wealth of information on here, I simply wouldn’t wish any one else to endure my experience and costs involved.

Thanks Steve

[mgcjag]

Hi Paul....ok..I will put up a new thread...specific to roller bearings....lets see what answers we get...no theory just practical answers.....Steve

[Paul bow]

Fantastic Steve.. be nice to get a broad view of it

[PierreW]

The same disaster happened to me last year on my MK2. New piece from Barratt. I replaced it with a bearing that would be an Upgrade (Barratt dixit!)....I don't know if it's true...

[JulianBarratt]

This thread is a few weeks old now but i just wanted to update the situation.

We had the failed bearing back from the original poster (with whom I have been in close contact) and this was sent to B&B for investigation. Unfortunately, it was not possible to be certain of the root cause of the issue because we were unable to return the full clutch kit since (as detailed above) the bearing was replaced along with the original plate and cover. This is understandable from the customers viewpoint but also from the B&B viewpoint.

It is the view of our technicians that the likely root cause here (although not proven) was that the issue was caused by there being some damage to the bearing prior to fitment - quite possibly not visible. This could have come from any number of sources - damage in transit, handling, storage etc. Its not possible to be 100% sure but this is our best guess.

We have resolved this issue with the original poster of this thread.

In addition - this is the only "live" issue we have with these bearing and we do not have a record of similar repeated instances with the current supply of these clutch kits. It is our view that the kits currently available may not be able to use some of the original materials available in the 1960s (on environmental grounds) but they represent a good, reliable part that is fit for purpose. We will, of course, keep our eye on this should anything change.

[mgcjag]

Hi Julian.....many thanks for the update....Steve