Damn CRB

[F355GTS]

And just to add an opposing view when I spoke with Dave @ Superclutch who said the last thing you should have is preload and their instructions require a 3mm gap between bearing face and fingers

 

 

 

Mark

[John Vine]

Ozzy,

 

Since fitting my double springs (April 2003), I've done over 11K miles (mixed road and track), and the CRB seems to be operating perfectly, with a lovely sweet clutch action and a complete absence of noise. (And if that's not a Providence-tempting statement, I'd like to know what is!)

 

Mark,

 

I don't doubt that Superclutch know a huge amount about clutches, but do they know more about this particular CRB than INA, the designer and manufacturer, and Ford, the primary user? When the Technical Engineering people at INA tell me they are adamant that this CRB requires a pre-load, and Ford implement exactly what INA recommend by means of a tensioning quadrant, I think I know whose advice I'd be inclined to run with! Perhaps Dave is thinking of the old-style carbon-faced CRBs, where constant contact was indeed a no-no?

 

JV

[John Vine]

Ozzy,

 

Obviously, if it goes again, I don't think they'll want to know a 3rd time!

But if they repair something under warranty, and the repair fails, aren't they obliged to sort it out?

 

I'm still left wondering whether or not CC now accept that there's a problem (of premature CRB failure) with the way the INA CRB is installed. I understand they're now replacing the INA CRB with one from SKF, in an attempt to solve this. If the pre-load generated by the standard pedal-spring set-up is sufficient to meet SKF's spec, I guess they'll succeed.

 

But, as far as the INA CRB is concerned (and the SKF one too, if the pre-load spec isn't met), I'm not convinced that CC have addressed the basic problem (which, IMHO, is a lack of adequate pre-load). CC agreed with me back in 2003 that a pre-load was indeed necessary, and assured me that the standard pedal return spring would achieve this (applying a force of about 80N). The question in my mind at the time (and now) was whether the actual pre-load was in fact as high as this, as my measurements indicated that it could be as low as 15N. Interestingly, CC agreed with my figures. They went on to say that, even on their own measurements, the pre-load was "marginal", so they recommended I fitted an extra spring!

 

I've heard nothing since to convince me that what I believe to be the fundamental problem (the design of the clutch operating mechanism) has been fixed, at least as far as the INA CRB is concerned. I understand that the SKF CRB also requires a pre-load, but less (at 45N?) than the INA one. Assuming that the clutch pedal design remains the same, changing to the SKF unit may solve the problem, but, then again, may not if the actual pre-load is, as I calculated, around 15N.

 

If you plan to retain the INA CRB, my advice is to ensure you set up a pre-load in the range 80-120N. If, on the other hand, you plan to move to the SKF unit, I think it would be wise to find out (from SKF? from CC?) what the pre-load requirement is, and then ensure you have a pre-load to suit.

 

JV

[F355GTS]

John

 

Is preload the problem though? Many INA CRB's have lasted for ages with the 'std' Caterham preload, the problem only seems to exist with CRB's manufactured more recently by INA in Brazil. Caterham seem to have recognised this and changed bearing supplier.

 

IIRC Superclutch differentiate between Race/Track use and Road use as to whether preload should be applied, I suppose alos to be fair they don't recommend the use of the INA bearing but specify and all steel, quality item

 

Mark

[John Vine]

Mark,

 

Good point, but I don't think it's correct to say the failures are limited to the Brazilian item. FWIW, both of my failed INA CRBs were of German rather than Brazilian manufacture.

 

However, I can't explain why some owners get early or repeat CRB failures, while others seem to cruise along merrily with not a squeak! I suppose one possible variable might be clutch-riding (or, at least, using the clutch pedal as a handy footrest), thereby applying some pre-load, albeit inadvertently?

 

JV

[Ozzy]

Thanks for getting back to us John. I know that CC have fitted the new bearing to my car this time around, but not sure about the pre-load for this one. I don't think the spring on my car is applying any pressure whatsoever. As mentioned by someone else, you can almost feel the pedal lifting under acceleration. It's that limp! It's fairly straightforward to mimic what you suggested in your article, but I wonder if this would be too much pressure for this new type bearing. Maybe I should follow your instructions on fitting these, but stretch the springs a little bit, at least that way there would be some tension. One things for certain, the existing spring on my car is doing absolutely nothing.

 

Thanks for responding.

 

Oz.

 

Still Shaking.

 

6 speed 1600k Supersport

(keep forgetting to tell people what it is!)

[John Vine]

Ozzy,

 

When I first saw the inside of my pedal box back in 1999, it struck me that the sole purpose of the pedal spring was to apply sufficient tension to the clutch cable to prevent the nipple at the clutch end from popping out of the clutch fork. Six years on, I'm still not sure whether it's designed to have any other purpose. If not, the limited pre-load that it does apply would seem to be purely fortuitous.

 

I don't know what pre-load (if any) the SKF CRB requires, so I can't advise, but I guess you could always ask CC. To obtain SKF's view, I've just sent a query via their website, and will post their answer. I quoted part number FRA174C. Is that correct?

 

JV

[Bricol]

Think about it, as long as what ever spring you attach isn't strong enough to actually operate the clutch, then you aren't going to do anything to the bearing. It is designed to operate under the load required to disengage the clutch.

 

The only problem you will get it cable stretch - which is what the quadrant assembly on the top of a tin top clutch pedal does - as you operate the pedal, it automatically takes up any slack. I wonder if there may be a marketing opportunity there? Remind me in a month or so when I'm back in the UK from dragging the yanks out of the do-do again . . .

 

Pre-load doesn't only ensure the bearing spins, it takes up the internal clearances in the bearing to the designed running fits - if it's loose, the races can slide over the rollers rather than spin.

 

Good to know from John it all appears to be working. And I'd certainly go with him on believing the tech reps from the bearing companies rather than the fitter.

 

Does it make it any more believable if I stake my profession qualifications on the line as well as my mechanical experience?

 

Bri

 

BEng (Hons) MIMechE

 

(too tight to pay them any more money to be a CEng . . .)

 

[MartinWoodham]

just replaced by CRB over the weekend. Managed to smuggle it out without removing the engine - just undid as little as possible and eased the block forwards off the bellhousing by about 4 inches - enough to swap the CRBs over.

 

The old one was a right state inside - I was expecting the face where it presses on the clutch to be worn badly, but the real prob was inside the bearing - there's a kind of castellated washer type thing retaining the bearing, and this was broken into 3 pieces - no doubt the graunching noise was those 3 bits floating around against each other.

 

New one has a different design - so hopefully no probs now - although I found the new one was a very light fit onto the actuating lever, where the old one was very tight....hope it stays on.....

 

Martin

Roadsports B

If everything's under control you're going too slow (Emmerson Fittipaldi)

[Nick Green]

I did a slightly different approach from John V's extra spring method, and shortened the existing single spring to get the preload, attempting to measure it by pulling with a spring balance and applying a bit of trigonometry.

 

The first INA bearing on my car lasted about 9k miles. This was replaced with an identical INA bearing. Don't know country of manufacture of either bearing.

 

Before learning of the preload requirement, I disconnected the pedal spring altogether for the 2nd CRB, and ran with no preload at all for about 5k miles. I could put my foot under the clutch pedal and lift the CRB clear of the clutch fingers. This is a greater mileage than a number of the failure examples quoted in this thread alone.

 

Then I put the shortened spring back on, tensioned as accurately as I could manage. This same CRB has now done around 12k miles total.

 

Regulars of the se7ens list from around 1998/1999 would have seen plenty of emails on there about CRB failures.

[graham bass]

Gareth we can probably organise a "change your crb day" and do a job lot.

I think mines got to come out again as well ☹️

This time I'll change the whole clutch not just the crb.....

[John Vine]

An update for those of you who have experienced (INA) CRB problems....

 

Since I applied my pre-load mod back in May 2003 (details here), I've had absolutely no more CRB problems, and I've done over 22,000 miles (mixed road and track) since. So, it does seem to work!

 

JV

 

[Colin Heseltine]

I have a feeling that listening to the noises from my clutch (on way back from 50th) when pedal depressed that my CRB is on its way out. I think this has done around 7K miles. Interested in knowing how easy it was for Martin to swap his without removing engine from car?.

 

Colin

[Kevsta]

Looks like I'll be adding this to the list of 'upgrades' over the winter as I will have my engine/box out and was going to change the CRB as a service item...maybe for the last time!

[nickh7]

30k miles and I am getting some squeal after a long high speed run its sound terrible and then just goes away, I want to look at the engine too this winter so will do the two together if I can save all the hassle of the Okie Cokey engine

 

Nick h

 

Its Yellow And Black and Makes me 😬here

[MartinWoodham]

Colin *arrowup* , it was fairly straightforward, Stephen Grant did a writeup of it here

The car has now done another 3k ish miles, maybe half of these on track, with no problems at all.

 

Martin

Aero'd supersported ex-Roadsports B...anyone got a cheap LSD/ 6 speed box?

[stephen grant]

 

Having now taken the engine entirely out for a bit of DVA magic this summer, I think you do save quite a bit of time using Martin's method for changing the CRB, rather than taking the engine completely out. Far less stuff to disconnect and you don't need to drain the oil either.

 

stephen

 

[CAB]

Hello Gents

My new clutch release bearing is in the post.....

I have had a look at Stephen Grant's write-up. Is it possible to go one step further and remove the engine whilst leaving the gearbox in the car? I have only ever taken the engine and box out at the same time. I was thinking of setting up the cam timing/fitting a new cambelt at the same time and I would rather do this with the engine on the bench rather than in the car.

Also can anyone confirm what preload is needed for the SKF bearing?

Cheers

CAB

[John Vine]

Chris,

 

As noted here, I'm told the pre-load for the SKF CRB is 50-100N (so a little less than the 80-120N for the INA item).

 

JV

[stephen grant]

CAB - it's no problem to remove the engine and leave the box in place; I suspect that most people here do that unless there's a reason to remove the gearbox. You obviously will have to disconnect all the electricals, drain the oil, etc., etc., and you'll probably need to remove the alternator and perhaps some other bits to clear the engine bay diagonals.

 

Remember also to support the gearbox.

 

For me, mating the engine and the gearbox back up again is a bit of a slow process, but just make sure that the angle of the two is the same as the block slides back onto the shaft. If it gets stuck with a couple of inches to go, try turning the crank a little with a socket on the end, go for a cuppa, adjust the angle of the box a bit, etc., and it'll go on eventually....

 

stephen

 

 

Edited by - stephen grant on 11 Oct 2007 09:54:44

[CAB]

Thanks Stephen

I'll probably just attempt to remove just the engine. Removing the box as well is a pain; to get to the gear lever mounting bolts I need to remove the tunnel cover which means removing the seats. Also there is the speedo drive to come off and the gearbox will have to be drained of it's fresh oil. Then there is a matter of storing the gearbox whilst it is out of the car. I expect I will end up taking the box out when I can't get it to line up though....

Cheers

CAB

[CAB]

Hello

Well it is all back together with the new CRB in. I thought that I would add a few notes to help anyone else who attempts it. In the end rather than just pull the engine forward and change the CRB I dragged it out completley and removed the sump foam and fitted a new timing belt and adjustable cam pulleys (1.8SS K series). It was much easier to these jobs with the engine on a stand rather than grovelling around under the car. I had to remove the Apollo tank, starter, alternator and the oil pressure sender (this just caught as I lifted the engine out). That exhaust manifold (standard short primary 4 into 1) is a pig to remove especially if you have studs fitted. I had to lift the engine and move it to get the manifold over the studs. It can just about be removed/reinstalled with the studs out, starter and water rail off with the engine in the car if you take off the lamda sensor off as well. I replaced the studs with cap headed bolts. I wanted to make sure that I could do this as I had planned to fit a 4-2-1 SLR/VHPD type of exhaust at a later date and I didn't want to have to take the engine out again to get the standard manifold off. It takes a bit of twisting and turning to get it in and out but it can be done. When I refitted it I put it in before the starter and then tied it back out of the way. That 17mm nut on the starter is very hard to get at, in the end I had to grind down a spanner.

When I put the engine back in with a hoist I used a trolley jack to adjust the angle of the engine relative to the gearbox (that was still in the car). With the input shaft engaged against the spigot bearing and the faces of the engine and bellhousing parallel I then used two very long M12 bolts to keep it in line. The bolts (from B&Q) pass forward through the top two bellhousing holes and are screwed into the holes in the block. With the engine lined up the two can be pushed together quite easily if you have an extra pair of hands to rotate the crank.

Thanks to all who offered advice.

CAB

[John Vine]

Chris,

Glad it's all back together again. Out of interest, what was the condition of your old CRB (and over what mileage)?

 

JV

[CAB]

John

The CRB had about 9000 miles on it when it started complaining. It didn't look or feel to be in too bad a condition but I removed it only a few miles after the noise started. I have put the twin springs on the clutch arm as per the article but with the lower preload for the new type of bearing. I'll let you kow how it goes....

Cheers.

CAB

[John Vine]

Good luck with the mod, Chris. If my experience is anything to go by (over 24K miles now), you'll not get any more CRB problems.

 

JV