Delberts Wallet Posted May 31, 2005 Share Posted May 31, 2005 I replaced my CRB last october and the damn thing has started sqealing again Not happy. I did the job myself so I guess I can't complain to CC apart from trying to get a replacement CRB FOC (FAB...etc). It now mean another engine out session and the car off the road for a couple of days. Gareth Blue and Carbon 6 Speed Supersport with new wheels Edited by - Gareth Harrold on 31 May 2005 18:15:29 Link to comment Share on other sites More sharing options...
timbo Posted May 31, 2005 Share Posted May 31, 2005 just think.... you'll get a chance to clean the engine bay while its out 😬 Emerald Isle's 1st SV 148lbft @ 6091rpm/182bhp @ 6690rpm engineered for low revs Link to comment Share on other sites More sharing options...
Delberts Wallet Posted May 31, 2005 Author Share Posted May 31, 2005 Yeah...thanks for that Gareth Blue and Carbon 6 Speed Supersport with new wheels Edited by - Gareth Harrold on 31 May 2005 18:32:56 Link to comment Share on other sites More sharing options...
mav Posted May 31, 2005 Share Posted May 31, 2005 how about not taking the engine out? Just split the engine / belhousing and remove the bearing? Oh, you've not got an sv have you Link to comment Share on other sites More sharing options...
Delberts Wallet Posted May 31, 2005 Author Share Posted May 31, 2005 I know what I'd rather have 😬 Gareth Blue and Carbon 6 Speed Supersport with new wheels Link to comment Share on other sites More sharing options...
caterhamnut Posted May 31, 2005 Share Posted May 31, 2005 I think that Caterham are now selling/fitting a CRB from a different supplier - not sure when they changed, but the one we fitted to frankyknuckles car a few weeks back was certainly visually slightly different.... Big update! here 80,000miles in 3 years plus Link to comment Share on other sites More sharing options...
knowley Posted May 31, 2005 Share Posted May 31, 2005 I got an old style one of them around last October, guess mine will be going again soon ☹️ Link to comment Share on other sites More sharing options...
Colin Mill Posted May 31, 2005 Share Posted May 31, 2005 Hi Gareth Sorry to hear you have the dreaded CRB failure. Can I ask if you were running the standard pre-load or a higher preload? I think it was John Vine who wrote an article last year in LF making a very good case for some extra springing which I'm very much hoping will ward off the problem. Link to comment Share on other sites More sharing options...
Myles Posted May 31, 2005 Share Posted May 31, 2005 I think that Caterham are now selling/fitting a CRB from a different supplier - not sure when they changed, but the one we fitted to frankyknuckles car a few weeks back was certainly visually slightly different.... Sometime around Christmas - that's when I got my 'new' style one. Piccies and some (worrying) measurements on the site halfway down here Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
stevefoster Posted May 31, 2005 Share Posted May 31, 2005 Is this comfirmed as a 'K' or a batch / age related thing? I've never had an probs with the two I have used with my VX or any of my 7's before. Just wondering, do VX's / XF's suffer this? Hants (North) and Berkshire Area club site here My racing info site here Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted May 31, 2005 Share Posted May 31, 2005 Good chance to get some info from all you CRB boffins out there! (should be tech talk I know!!!) I was always under the impression that when I used to run my own cars (as opposed to Co vehicles) whenever I had that rare chance to change a CRB as in my Triumph Spitfire etc it had to have a measured clearance from the clutch pressure plate release 'fingers' when at rest. There was a spring to pull the release arm back. The books said that if it was touching the fingers it would wear out the bearing prematurely. Like resting your foot on the clutch pedal etc. Now we have the opposite position given with the Caterham CRB that HAS to be in contact with the fingers with a certain amount of (disputed) pressure. I assume this is because with Caterham fast shifts the bearing could skid up to speed and therefore melt the plastic housing. Daft idea making a bearing in plastic I think anyway!!!! If they were in steel, could they probably run with a slight gap? I mean apart from a few sharp short shifts etc surely the bearing isn't being spun up as much as it is in its resting state ie. NOT changing gear. Certainly those long motorway drags (c'mon; you can't use 'B' roads all the time) mean the difference between a bearing running constantly and one that isn't. Opinions 🤔 🤔 🤔 Cheers, Chris Link to comment Share on other sites More sharing options...
Ian B Posted May 31, 2005 Share Posted May 31, 2005 I was thinking the same thing Chris 😳 Ian - MI 5EVN - Slightly Vider SVelte model 😬 now repainted to match the Autocom headsets 😳 Link to comment Share on other sites More sharing options...
Colin Mill Posted May 31, 2005 Share Posted May 31, 2005 Hi Chris When I came to put the car together my initial thoughts on the CRB were exactly on the same lines as your comments. However, having kicked the problem about somewhat on BC I decided to go along with the higher pre-load largely because the bearing manufacturers seem to have designed it for a preload of 80 to 120N and also because several other models of car I looked at have preloaded CRBs. (I guess the change in this bit of car design came about while I wasn't looking!) From my measurements the bearing preload is 2.55 times the cable tension and I found that standard spring setup only gives 1.1kgf (10.8N) of cable tension and thus only 27.5N of bearing preload. I found I could get to the recommended preload by shortening up the spring. The LF article shows the use of two springs. Link to comment Share on other sites More sharing options...
Mr Locust Posted June 1, 2005 Share Posted June 1, 2005 Gareth, did you fit a spring on the pedal pulling the cable tight at all times? Ian Green and Silver Roadsport 😬 Link to comment Share on other sites More sharing options...
Delberts Wallet Posted June 1, 2005 Author Share Posted June 1, 2005 The car already had a spring fitted. When I replaced it back in Oct I made it a little tighter in the hope that it would stop this from happening again...so soon ☹️ Gareth Blue and Carbon 6 Speed Supersport with new wheels Link to comment Share on other sites More sharing options...
stevefoster Posted June 1, 2005 Share Posted June 1, 2005 I ran with just the original spring and on bumpy B road I swear I could feel the pedal hopping up and down. Since fitting an extra spring all is firmer. I'm not suggesting that this causes the CRB to wear out, just and observation... Come on... any VX or XF owner had CRB failure? Hants (North) and Berkshire Area club site here My racing info site here Link to comment Share on other sites More sharing options...
neil.cavanagh Posted June 1, 2005 Share Posted June 1, 2005 mine has started making a grrrnnarrl noise when in neutral with your foot off the clutch pedal. Is this the 1st sign that mine is about to fail?? *mad* Still its lasted 2 years and 19K miles which is pretty good for a K CRB!! 😬 Link to comment Share on other sites More sharing options...
Bricol Posted June 1, 2005 Share Posted June 1, 2005 To reuse an old analogy I used last time this appeared - if you watch an aircraft coming into land - the wheels are stationary - then they hit the ground and have to spin up pretty quick - they skid for a while -hence the tyre smoke. Think of your bearing, pulled away from the clutch - you rev the engine up the gears - and then shove a stationary bearing into the fast rotating clutch, instead of it being spun up in sync with it. It doesn't necessarily melt the plastic carrier, its the fact that contact face skids on the clutch, the internal carrier'/separator has inertia, the rollers inside the bearing skid as the contact face speeds up - skidding means wear - wear means more wear, more skidding, more heat (an dif the internal carrier happens to be plastic . . ), the grease overheats, more skidding . . . . All release bearings now run in full contact with the clutch and have done for a long time - old carbon release bearngs wouldn't - they would wear out in no time. Runnning a bearing at a nice constant speed, as it would at constant revs, is probably the nicest situation the bearing could be in - no excessive load, nice speed, the rollers roll, the grease is lubricating nicely - wonderful easy life. I talked to SKF - the old style bearing - requires a preload of 90N. The replacements seem to be INA - which according to them requires a preload of 40 -50N . . . Bri Link to comment Share on other sites More sharing options...
Colin Mill Posted June 1, 2005 Share Posted June 1, 2005 Hi Bricol Not sure that the running in full contact is universal. I have looked at the Haynes manuals for a 5 series BMW, the Rover 400 series and the Rover Metro/100 and in none of those is there any sign of a preload spring. From previous discussions its not the bearing that is the problem but the plastic carrier (that from my tests melts at about 190C) Link to comment Share on other sites More sharing options...
Myles Posted June 1, 2005 Share Posted June 1, 2005 Is this the 1st sign that mine is about to fail?? Still its lasted 2 years and 19K miles which is pretty good for a K CRB!! No - this is a TADTS - CRB failure is (often AFAIK) presaged by nasty noises when you put your foot *on* to the clutch-pedal (see Bricol's explanation) - rumbles with your foot off (often only when hot) are usually just due to the layshaft (I think...) rattling around. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
neil.cavanagh Posted June 1, 2005 Share Posted June 1, 2005 😬 *thumbup* thanks Myles...I was hoping that was the way round... clutch up gurgle noises...stop when clutch foot down is OK. clutch foot down and still gurgle noises bad.... Link to comment Share on other sites More sharing options...
John Vine Posted June 3, 2005 Share Posted June 3, 2005 I talked to SKF - the old style bearing - requires a preload of 90N. The replacements seem to be INA - which according to them requires a preload of 40 -50NI think it's probably the other way round. The "old" CRB was from INA, and the "new" is, I believe, from SKF. The INA CRB requires a pre-load of 80-120N. I don't know what the SKF one requires, but I'm told it's less. From previous discussions its not the bearing that is the problem but the plastic carrierI'd claim that neither is a problem, provided the CRB is pre-loaded correctly. Given that Ford use the INA CRB in the Sierra (not a car renowned for CRB failures), I'd say the construction was well up to it. JV Edited by - John Vine on 3 Jun 2005 20:56:36 Link to comment Share on other sites More sharing options...
Bricol Posted June 3, 2005 Share Posted June 3, 2005 Yep - when I looked back I realised I'd got it the wrong way round - it was a while ago - and I can't remember which one I've now got in the car (car in UK, I'm not). I do know it's the one with a lower pre-load figure. It took a while to get the info from SKF, even allowing for stirring things up from the industrial side I normally deal with. I too reckon that it must be up to the job in the orginal Sierra when you think of how many of those have been on the road and how many would not have been treated gently. Never had any problems with the same bearing in 7 years and a lot of miles in a Westie. I was pretty amazed ot hear the rumbling from mine after only 12000 miles - up to then I don;t think I'd ever had a bearing fail in any car - and I don't think I ever changed it as a precaution in any of them even when changing the friction plate - too tight to do so! As for the pre-load spring - if it's a cable clutch, it's probably on the top of the pedal - a nice little quadrant design. With hydraulics -no idea - I guess there is a preset stop it rests against - knew I should have taken more notice of the Integrale one - which is pull rather than a push. I'm certainly going to engineer in some more pre-load on mine to keep it nicely spinning. Bri Link to comment Share on other sites More sharing options...
Ozzy Posted June 3, 2005 Share Posted June 3, 2005 John. As a matter of interest, since you wrote the article in LF, and fitted the extra springs, how many miles has this now lasted?? I'm curious, as I had to have the crb replaced under warranty at CC last year, and within 400 miles had the odd rumble with the brand new bearing. I was so worried that this would'nt last, that CC agreed to warranty the bearing for 3000 miles. Sure enough, this failed again recently, and they have replaced it again with the new type bearing. Obviously, if it goes again, I don't think they'll want to know a 3rd time! The spring thats on the pedal at the moment seems to have virtually no tension at all. I wonder if I should apply your method, to try and prolong the life. I find all this incredible really, I've never had to replace a clutch bearing on all the cars I've had over the years, and I've had plenty of heaps in the past! To expect 5000/6000 miles if you're lucky is plain ridiculous. There has to be some inherent design fault somewhere. Still Shaking. 6 speed 1600k Supersport (keep forgetting to tell people what it is!) Link to comment Share on other sites More sharing options...
Ozzy Posted June 4, 2005 Share Posted June 4, 2005 If you do happen to spot this John. Would appreciate your thoughts. Oz. Still Shaking. 6 speed 1600k Supersport (keep forgetting to tell people what it is!) Link to comment Share on other sites More sharing options...
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