Keith Posted June 28, 2014 Share Posted June 28, 2014 I've owned my 12/50 for 30 years now, and in all that time I've always had problems with clutch judder, especially when hot. I've changed pretty much everything now, new old stock clutch, engine back plate and it still does it.Is there a way of making the coil spring clutches work properly, or should I just bite the bullet and swap it for the diaphragm version?K Quote Link to comment Share on other sites More sharing options...
herald948 Posted June 28, 2014 Share Posted June 28, 2014 How are the engine and gearbox mounts? Worn mounts, especially on the rear of the gearbox, can cause judder. Quote Link to comment Share on other sites More sharing options...
Jordon T Posted June 28, 2014 Share Posted June 28, 2014 My 67 1200 has clutch judder but only when reversing. It has a diaphragm clutch. New engine mounts. New gearbox mounts. New clutch. Still the same.I tend to rev the engine a little higher when disengaging the clutch. Helps a little. Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 29, 2014 Share Posted June 29, 2014 also check the diff front mounts these go soft the diff can tramp on take up.Keith its easy to fit a diaphragm but you are likely to need to add a new dowel hole in the flywheel, and get the later longer throw out carrier.its a much more refined operation and can be a lot cheaper . not an engineering solution but we centralised the new cover by adding a pipe olive to each bolt to take up the hole clearanceand drilled the dowel hole with a battery drill . tapped in a new dowel and it was fine , did make a simple rig to rotate the flywheel and check dowls concentricy with a dial gauge , but certainly DIY possible.if you have a local engineering shop then thats probably best.pete Quote Link to comment Share on other sites More sharing options...
Keith Posted June 29, 2014 Author Share Posted June 29, 2014 I've probably got most of the bits to do the swap kicking around. As far as I can tell it's flywheel, slave cylinder, bearing carrier and the clutch itself. Is there anything else?I just find it frustrating that I can't make the coil spring clutch work properly, I can't believe they were that bad when new, or were they?K Quote Link to comment Share on other sites More sharing options...
Mark Hammond Posted June 29, 2014 Share Posted June 29, 2014 I think so. I have known mine since new and been driving it from 12000 miles old and there is definitely a technique in pulling away in 1st or reverse. Age won't help either.Mark Quote Link to comment Share on other sites More sharing options...
Keith Posted June 29, 2014 Author Share Posted June 29, 2014 According to the parts book the clutch lever changed as well with introduction on the diaphragm clutch. All the ones in my parts heap look the same, irrespective of what bearing and carrier is fitted. Anyone know what the difference is, and how to tell one from t'other?K Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 30, 2014 Share Posted June 30, 2014 cant help about the changes but if you want to persist with the coil unit you could fit it to a dummy flywheel and check the throwout platten is running flat with a dial indiactor across its surface it there is runout you can un peen the post nuts and adjust the heights , any throw out runout will be turned into judder due to offset contact loads might be worth a play . whats more anoying is I had in a cupboard at work a churchill coil aligning face plate, been there for 40 years and never used , too small for truck stuff, and it went in the skip when things closed down, just 1 year before i bought the vit6 with a coil cover ...Pah.... if only !!!pete Quote Link to comment Share on other sites More sharing options...
Keith Posted June 30, 2014 Author Share Posted June 30, 2014 I think the parts book reference may refer to the whole lever assembly, rather than just the the alloy lever on it's own, which would have the different bearing carrier attached hence have a different part number. Does that seem reasonable?Started playing with dial gauges today to see if I can work out what's wrong as you suggest Pete. I thought I'd start by checking the flywheel runout. I wasn't getting any sensible readings so I thought I'd give it tug to check the end float. I got almost a complete revolution of the gauge. Argh, 100 thou, thrust washer dropped I thought! I'd dropped the sump before I realised that the gauge, which is not the one I normally use, is calibrated in 0.0001". Maybe I should take up a different hobby. :-/K Quote Link to comment Share on other sites More sharing options...
herald948 Posted July 1, 2014 Share Posted July 1, 2014 Keith wrote:I just find it frustrating that I can't make the coil spring clutch work properly, I can't believe they were that bad when new, or were they?Having driven Heralds off and on since about 1969, I would have to say NO, they were not that bad when new. Further, they don't have to be that bad now! Sometime around 2004 or so, I "blew up" the coil spring clutch in my '62 and replaced it with NOS Borg & Beck bits. I also replaced the rear engine (gearbox) mounts at the time, and it was fine after that. Your mileage may vary.... Quote Link to comment Share on other sites More sharing options...
Keith Posted July 1, 2014 Author Share Posted July 1, 2014 That's what I thought Andy, it was NOS about 15,000 miles ago, and still looks new. There is a lot of oil around the inside of the bellhousing though. I'm now pinning my hopes on a new scroll gearbox oil seal that I've just ordered from Rimmers.The problem only occurs when it gets hot so it could be as simple as that.Keith Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 1, 2014 Share Posted July 1, 2014 hey Keith this may be a play on words but if your front cover has a scroll it wont have a 'seal' if there is any dark markings around the disc that would indicate oil is in the linings, if its ferrodo stuff colour across its facing then its 'not 'if you still play with the dummy set up then they use 3 dummy disc thickness buttons at 0.305" thick, this replicates the discand should give e release height of 2.22" max.if you lightly clamp the disc facings in a vice to just lightly compress the wavy plates then the disc should be around the same 0.305" thick, if by chance you have a diaphragm disc its thinner by about 2mm to start with Oh have you tried spec savers Ha ! Quote Link to comment Share on other sites More sharing options...
Keith Posted July 8, 2014 Author Share Posted July 8, 2014 Right, I've been busy sorting out the gearbox, that's done now so back to the clutch. I think I may have found what was causing the problem! Quote Link to comment Share on other sites More sharing options...
Mark Hammond Posted July 8, 2014 Share Posted July 8, 2014 Yep, that'll do it.....Mark Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 8, 2014 Share Posted July 8, 2014 Keith its a classic, you know when ever you find the cause it never cures the problem live in hope pete Quote Link to comment Share on other sites More sharing options...
Keith Posted July 8, 2014 Author Share Posted July 8, 2014 But is it cause or effect?That was (I thought) a NOS Borg & Beck plate about 9000 miles ago. At least that's what I thought as it came out of a Borg & Beck box.I've never seen one that bad before, the centre is noticeably loose and rattly.Looking back through my old bits pile I found a clutch cover that I'd removed previously with a crack in the pressure plate.So maybe I've just been unlucky with a succession of duff bits, or maybe there is a root cause. I dare say I'll find out when I've got it all back together.K Quote Link to comment Share on other sites More sharing options...
ferny Posted July 9, 2014 Share Posted July 9, 2014 Myy NOS B&B didn't last long either. Maybe they had a period of making duff clutches? Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 9, 2014 Share Posted July 9, 2014 believe Borg and Beck/AP are now made under license by First Line , may be worth a check the engine back plate is 'flat' if the gearbox is a little out of line you can induce all sorts of cracks and fractures.had a giant wall chart from AP on the wall at work with all the classic failures on, unfortunate the charts gone the walls gone and the factory gone ...Im gone too Ha !Pete Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 9, 2014 Share Posted July 9, 2014 here a fault chart from LK http://clutchnet.com/index.php?option=com_docman&task=doc_download&gid=2&Itemid=129any google search finds some charts Pete Quote Link to comment Share on other sites More sharing options...
Keith Posted July 9, 2014 Author Share Posted July 9, 2014 Thanks Pete, that's a useful chart. The engine back plate was replaced last time and still looks to be flat.K Quote Link to comment Share on other sites More sharing options...
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