Clutch release bearing

[Colin_T]

So my clutch release bearing decided to give up on me at Snetterton yesterday. Not sure exactly what’s failed, there is some kind of bearing still in existence although squeaky. Managed to adjust the hell out of the cable and remove the pedal stop and drive home with minimal clutch use or gear changes, will do a proper post mortem once engine is out…. 

was a Sachs item fitted only couple months ago. 

is there an upgrade, mod, or alternative available for these?

I see a YouTube video of someone using a 2wd YB Cosworth release bearing ??? ( Burton ECB113 )

R500 K , 6 speed caterham box. 

[2cv7]

I had put one  in mine. I have just taken the box out to fit a Pgm Clutch arm and it was fine after 10,000 miles.

It may be that your clutch arm has failed.

K series with Caterham dry sump and 6 speed.

[John Vine]

2 hours ago, 2cv7 said:

I had put one  in mine. I have just taken the box out to fit a Pgm Clutch arm and it was fine after 10,000 miles.

It may be that your clutch arm has failed.

K series with Caterham dry sump and 6 speed.

I suspect the clutch arm too, especially if it's CC's original modified part.  A failed CRB on its own would be unlikely to need so much cable adjustment.

 PGM upgrade

JV

[Colin_T]

1 hour ago, John Vine said:

I suspect the clutch arm too, especially if it's CC's original modified part.  A failed CRB on its own would be unlikely to need so much cable adjustment.

 PGM upgrade

JV

Perfect, even if that’s not the fault it still looks a worthy upgrade to do whilst it’s all out. 

[John Vine]

Another thought...

If you haven't already done so, it would be a good idea to ensure that your CRB has adequate pre-load.  More info in this Guide. 

(Note that spring CQ13 is no longer available from CC or Redline, so you'll need to find an alternative of about the same spring rate.)

JV

[Colin_T]

Just had a Quick Look through the hole in the gearbox casing with a torch (couldn’t quite get it with my phone torch at the track)

I can see the back of the release bearing, I.e what would locate on the clutch fork is all mangled and melted.

now, I vaguely remember when I jumped in the car prior to that session I accidentally flicked the clutch pedal with my foot… I wonder if this allowed the release bearing to fall off its little locating tabs? Or fallen off one and was sat on the wonk or something.

either way it doesn’t look impressed 🤣

 

[John Vine]

5 hours ago, Colin_T said:

Just had a Quick Look through the hole in the gearbox casing with a torch (couldn’t quite get it with my phone torch at the track)

I can see the back of the release bearing, I.e what would locate on the clutch fork is all mangled and melted.

now, I vaguely remember when I jumped in the car prior to that session I accidentally flicked the clutch pedal with my foot… I wonder if this allowed the release bearing to fall off its little locating tabs? Or fallen off one and was sat on the wonk or something.

either way it doesn’t look impressed 🤣

 

I suppose that's a possibility, especially if the CRB doesn't correspond closely to the standard Ford dimensions.  A photo would be good if you can manage it.  Do you have access to a borescope/endoscope?

Out of interest, which Sachs CRB is fitted?

JV

[Colin_T]

That’s a good point… yes I do. I bought one of those eBay borescopes that plugs into your phone. I’ll get a pic of it. 

also I stand corrected on the sachs, it’s an SKF one. Assuming it’s the same one that was left in a box in the footwell of my car when the garage had the gearbox out it’s a VKC 2144 

and here’s current one…

 

also noticed tips of clutch fingers look all brown and rusty.. didn’t look like that when I had engine out in April. 
 

[John Vine]

Oooh -- scary pics!  Thanks for posting.

VKC 2144 is the SKF CRB that CC have supplied since around 2007 as an alternative to the "correct" (aka original) INA CRB as used by Ford.  The SKF ones I've seen are a slightly looser fit on the clutch fork but work ok.  They also (I believe) require a lower preload of 50-100N, compared to the INA 80-120N.

It looks like the black plastic CRB carrier has melted, or is that black goo exuded grease?   Either way, it would appear to have been severely overheating (which is a classic symptom of inadequte pre-load), but I'm suprised that it's happened in just two months. 

Maybe the clutch fork is ok after all?  I guess you won't know what's really happened until the engine comes out. 

By the way, when you say "garage", did they replace the CRB recently?  Do you think they made a mess of it?  Is the work guaranteed?  (I guess they'd love to see your pics!)

JV

 

 

[Colin_T]

Yes all the black plastic has turned to release bearing fondue!

garage/dealer had fitted the new CRB but was all fine. I very much doubt anything of their doing or anything to do with defect of the part itself. they actually had engine and gearbox out trying to sort a transmission noise, then i ultimately fixed the problem myself shortly after, which meant taking the engine back out…. Which now looks like I’m doing again lol - luckily it’s not too bad to do. 

 I think it had come unclipped when I caught the pedal and it flicked up. I then managed 2 or 3 laps before it failed and I drove it back to the pits. Up until then it had been fine all day, no noises, felt like it had always done. 

i then of course drove home 100 miles, with minimal clutch use as possible, probably used the clutch more the last 20ft reversing into garage than the previous 100 miles, but still no doubt contributed to the wear and melty goodness. 
 

once it’s out I’ll give the fork a good checkover too. And the clutch cover as well to make sure that’s not been damaged, bent or excessive worn finger tips… and make sure I sweep out all traces for release bearing fondue .

[John Vine]

I think your hypothesis may well be correct. If the CRB became unclipped from the clutch fork, there would be little to prevent it spinning freely on its axis. The two mounting tabs on the fork would then chew up the plastic carrier (and maybe melt it too). This would also markedly increase the slack in the clutch cable.

JV

[Geoff Brown]

Also check for micro cracks emanating from the edges of the clutch cover. Can be a known problem with a K Series that I can testify to after the sides of the cover decided to semi detach themselves from the centre piece. Cracked in three positions !

[Colin_T]

2 hours ago, Geoff Brown said:

Also check for micro cracks emanating from the edges of the clutch cover. Can be a known problem with a K Series that I can testify to after the sides of the cover decided to semi detach themselves from the centre piece. Cracked in three positions !

Are you referring to where the cover bolts to the flywheel? 

[Geoff Brown]

On 08/06/2024 at 14:09, Colin_T said:

Are you referring to where the cover bolts to the flywheel? 

Yes.

[Mcalvert]

See also here when I documented the upgrade that was recommended to me and which has served me very well in the intervening 13 years: https://lowflying.caterhamlotus7.club/2010/2010_03_03_CRB.pdf

 

[SLR No.77]

My first Caterham (1995 K-Series) had a CRB with a metal carrier rather than the later plastic type and had very secure tabs that locked it to the clutch arm. When I fitted a dry sump system I was so unimpressed with quality of the replacement CRB I’d bought that I refitted the original. This was still going strong when I sold the car at 12 years old.

My current car (1999 K-Series) had had a plastic carrier CRB fitted and each time I’ve removed the engine it’s literally fallen off the clutch arm. I’ve kept refitting the same CRB though and it’s still fine probably 20 years since originally being fitted. Neither car has had a pre-load setup, just standard Caterham fitment.

I have to conclude that although the later CRBs do look to be pretty low quality, as long as they’re fitted correctly and stay in place all is fine. They’re a pretty close fit on the gearbox input shaft so even if not secure on the clutch arm it’s hard to see how it could become so misaligned to cause damage or self destruct.

Stu.

[Colin_T]

engines out. This is the release bearing. Bearing still spins but I suspect there’s no grease left in it. 
 

[Colin_T]

No evidence of it spinning, no wear inside the plastic sleeve part. It looks purely caused by excessive heat and just melted through itself. 

perhaps inadequate pre load has heated the bearing up ???? Thoughts ???? 

2 track days and maybe 500 road miles

good news though, no other internal damage.

i did buy a helix release bearing as wanted a good one… turns out thats just the same SKF one in a fancy box and twice the price, so thats getting returned. 

may make a trip to burtons tomorrow and pick up one of the ali housing ones and bearing and do a bit of modding in the lathe, and pay close attention to pre load springs on the cable set up.

I should be able to borrow a force meter from work to take out any of the guess work. 

 

[John Vine]

6 hours ago, Colin_T said:

perhaps inadequate pre load has heated the bearing up ???? Thoughts ????

 

Interesting! A lack of pre-load means that the CRB is not held in constant contact with the diaphragm spring fingers.  As a result, it has to accelerate from zero to crank speed every time the clutch pedal is pressed. This causes skidding and excessive friction-generated heat, which in turn leads to loss of lubricant and eventual bearing failure.

What surprises me is that all this seems to have happened to your CRB abnormally quickly.

IMO, a special or posh CRB isn't necessary. The standard item (preferably the INA part as specified by Ford) is perfectly suitable. All that is needed is the correct pre-load as specified by the CRB manufacturer. After all,  how many Sierras etc suffered from CRB failures?

JV

[John Vine]

Looking again at your photos, it seems that pieces have been sliced off the plastic carrier (red arrow).  Is that right?  If so, what might have caused that?  Also, what exactly is the damage to the central sleeve (yellow oval).

It might be worth sending that CRB to SKF for a technical assessment.  I sent one of my failed CRBs to INA (years ago now), and they provided a comprehensive report of what they thought had caused the failure.

JV

[Colin_T]

All from where the plastics melted.

The plastics just got pushed further and further into the bearing (or bearing further and further into the plastic )

 

so inner sleeve now protrudes bearing face, and on the back side the bearing is even past the “squared off” section of the bearing where the retaining clips are by a good 2mm or so. (Check side view) 
 

there is no obvious evidence of excessive heat on the clutch fingers, or the gearbox nose. And the actual inner surfaces of the plastic carrier where it slides up and down the gearbox nose still look in very good condition.

 

the bearing itself, although now scrubbing against the plastic, still turns easily. 

[Colin_T]

Anyone know how to actually get the clutch fork off??? 

[Colin_T]

Is it bellhousing off ?? 
 

answered my own question. Yes bellhousing off.

i assume it only needs a light smear of silicone on refitting around the selector fork o ring and mating faces, Not the 18gallons of sealant mine had holding it on - let’s just say it didn’t need the bolts 😅 

Edited June 16 by Colin_T

[John Vine]

2 hours ago, Colin_T said:

All from where the plastics melted.

The plastics just got pushed further and further into the bearing (or bearing further and further into the plastic )

 

so inner sleeve now protrudes bearing face, and on the back side the bearing is even past the “squared off” section of the bearing where the retaining clips are by a good 2mm or so. (Check side view) 
 

there is no obvious evidence of excessive heat on the clutch fingers, or the gearbox nose. And the actual inner surfaces of the plastic carrier where it slides up and down the gearbox nose still look in very good condition.

 

the bearing itself, although now scrubbing against the plastic, still turns easily. 

Thanks for the info.  That would explain why you needed to adjust the cable so much. 

I'm still surprised that all this wreckage occurred within just a couple of months.  I'm wondering whether there was a fault within the CRB itself.

JV

[John Vine]

2 hours ago, Colin_T said:

Anyone know how to actually get the clutch fork off??? 

I'm not familiar with the modified fork, but I'd imagine it would simply lift off the fulcrum pin in the same way as the standard Ford fork?

JV

Edited June 16 by John Vine
Fix typo