stephen grant Posted April 10, 2008 Share Posted April 10, 2008 I think I know where this one is going, but here's one last desperate call for help before I learn how to get the gearbox out.... Speedo stopped working a while back. The right-angle drive had come off the top hat. I put it back on, but it didn't help. I've fiddled around for a couple of weeks, testing the various components, with some slightly confusing results so I replaced the quill, the right-angle drive and the cable. New components on, same lack of speedo. Here's what I've found; 1) With the rear wheels up, in neutral, and the quill in the speedo drive/top hat, I can see that the quill rotates as I turn the wheels/prop shaft. I can only really test this at slow speed for obvious reasons. 2) The new angle-drive works fine; with the quill in the angle drive I can see the other end rotates 3) A drill on the gearbox end of the cable spins up the speedo to any speed you care to mention. So, on the face of it everything works. Except it doesn't. And if I disconnect the speedo and go for a drive, the cable isn't rotating. Obvious nasty thought; there's something slipping behind the top hat when it's all connected up and trying to rotate, meaning I have to take the box out to fix it. Question 1; I notice though that my top hat seems very loose (the circlip is there), it's extremely hard to get the angle drive onto the top hat and I can only get 3 or 4 turns on it before it's impossible to stop the top hat rotating with the nut on the angle drive that tightens onto it. Is this how it should be? There's no way I can get the angle drive to screw up tight on the top hat, even with a screwdriver behind the top hat to try to stop it turning. Could this be my problem? Question 2; Is there any point in me wrestling the circlip out and taking the top hat out? Is there anything behind there that could have got broken and that I can fix with the box in-situ? Question 3; If I have to get the box out, what's the best way, given that I'll be doing it single-handed? I've had the engine out a couple of times before, but I've always left the box behind. Should I bring the box out with the engine, or is it going to crashbash everywhere? Or should i lift the engine and then drop the gearbox down? Sorry for all the questions, thanks for reading - any help appreciated. I know the simple answer is to ditch the lot and get a wheel-driven speedo setup, but I'm really keen to stick to the standard caterham dials on the dash if I can..... Thanks, stephen Link to comment Share on other sites More sharing options...
luddites7 Posted April 11, 2008 Share Posted April 11, 2008 I am currently suffering exact same problems and get same results. I have now forced the quill into the speedo drive hoping it was just that slipping causing the problem. Issue i have now is my dedion tube was cracked so fitting a replacement this weekend - hopefully get the car out for a test and let you know if speedo now works - fingers crossed as its starting to hack me off now - just another issue. Jas Link to comment Share on other sites More sharing options...
Casbar Posted April 11, 2008 Share Posted April 11, 2008 If the quill turns then there is nothing wrong with the drive in the gearbox. The right angle drive should do up tight, hold the top hat with some long nose pliers and tighten it. If you can get the speedo to work by spinning the cable, then it looks like all the bits are working, have you tried fitting the right angle drive and seeing if the other side is spinning, ie put the rear of the car on axle stands and put the car in gear and test each bit. There is nothing behind the top hat, if it was the speedo drive, its a gear box strip down to sort it out, but if the quill spins that bit seems ok Link to comment Share on other sites More sharing options...
dave1968 Posted April 11, 2008 Share Posted April 11, 2008 Stephen I had a very similar problem a couple of weeks back. It turned out i had been supplied the wrong quill for the angle drive i had been supplied..... It seems there is one quill relating back to the VDO style guages and one for the newer caterham ones. I was supplied a vdo one which only worked in a certain position within the angle drive....meaning that i got very similar results to you in that you cold see everything turning etc then you put it all together and hey presto! b*gger all happened! Might be worth checking as obviously very quick and easy fix if it is the same problem Cheers Dave Link to comment Share on other sites More sharing options...
stephen grant Posted April 11, 2008 Author Share Posted April 11, 2008 Thanks all, Having slept on it, I'm sure that you are right - it must be that the angle-drive isn't tightening properly on the top hat. At the moment there doesn't seem to be any way for me to stop the top hat from turning, but I wonder if the thread is crudded up with road muck (the car was running for a fair few miles with the angle drive hanging off before I put it back on), or maybe the thread has got crossed and knackered. I'll spray copious amounts of WD40 on it this evening, try to clean everything off it and give it another go with a pair of pliers on the top hat If, as you say, the angle drive should go tight on the top-hat, then that must be my problem Dave - the quill that came out looked identical to the new one I was supplied by CC, so I think that's unlikely to be the cause; in both cases the quill just looks like a small section of the inner speedo cable. Thanks again stephen Edited by - stephen grant on 11 Apr 2008 09:27:18 Link to comment Share on other sites More sharing options...
dave1968 Posted April 11, 2008 Share Posted April 11, 2008 Stephen the two different quills do look pretty much identical to the eye as theres only a few thou' difference in them..... anyway good luck with it Dave Link to comment Share on other sites More sharing options...
stephen grant Posted April 11, 2008 Author Share Posted April 11, 2008 A-ha. Many thanks. Then I will check. I do note though that if I stick the quill into the new angle drive and turn it, I can see the other end turn as well. Actually, I presumably can test this anyway buy putting the drill on the quill that is in the angle drive and seeing if the speedo turns? Errr.....How do I know if I have a VDO-style gauge or the newer caterham one? I have an analogue odometer if that helps - I see that other folk have a digital one... stephen Edited by - stephen grant on 11 Apr 2008 10:27:25 Link to comment Share on other sites More sharing options...
dave1968 Posted April 11, 2008 Share Posted April 11, 2008 Stephen not sure how you tell re VDO / caterham guages?? probably its whats printed on the dial though (mine says caterham as its a caterham one so i guess the VDO guages have VDO printed on them) i had same dilema as u in that i put the quill in and turned it and the angle drive turned properly. However i found that if i inserted the quill all the way into the angle drive the quill turned on its own as it were, not turning the angle drive (and hence when installed on the car not turning the speedo cable / speedo). if i pulled the quill back out a few mm and turned it all was ok again......with the correct quill it didnt matter how far the quill was inserted, it always turned the angle drive prperly. Caterham mentioned the parts bins for the two quills were right necxt to each othe rin the stores and the picker had simply gone to the wrong one...... i hope im not sending you on a wild goose chase with this but its does sound pretty similar to the problem i had is all so may be worth checking before trying anything more costly. Dave Link to comment Share on other sites More sharing options...
stephen grant Posted April 11, 2008 Author Share Posted April 11, 2008 Ok, thanks - that's pretty easy for me to test then - I simply push the quill as far as I can into the angle drive and check that the other end still rotates Thanks again Dave - this is all much appreciated. I'll get there in the end... stephen Edited by - stephen grant on 11 Apr 2008 14:39:33 Link to comment Share on other sites More sharing options...
millsn Posted April 11, 2008 Share Posted April 11, 2008 I seem to recall it was possible to get tghe little drive (that sits inside the speed cable at the gearbox end) in wrong way round. Icould never actually close the drive onto the gearbox but it may be possible, have you tried putting it in the other way around? Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted April 12, 2008 Leadership Team Share Posted April 12, 2008 Stephen, VDO gauges were used prior to '96 and are labelled VDO on the gauge face, Caterham gauges (made by Caerbont) have been used since, and are labelled Caterham (obviously!). Stu. Link to comment Share on other sites More sharing options...
luddites7 Posted April 12, 2008 Share Posted April 12, 2008 I have to admit i did try the quill both ways round and it didnt seem to make any difference - its as if its about 5 mm too short. At least now i know i am not the only one with this issue 😬 Jas Link to comment Share on other sites More sharing options...
stephen grant Posted April 12, 2008 Author Share Posted April 12, 2008 Progress....of sorts. Cleaned up the threads on the top hat, got some long-nosed pliers on the back of it and got the angle drive nice and tight onto the top hat. Take it for a drive and - voila - the speedo bursts into life. But, wierdly, it's reading waaaaay too fast! 40mphish on the speedo is 28mphish on the GPS. 80 on the speedo is 56 on the GPS. This *has* to be a problem with the speedo itself, surely? It's the "Caterham" branded Caebert speedo (thanks Stu!), the older version that has analogue odometer & trip meter. Doesn't look like there's anything adjustable on the back of the speedo, certainly no sign of dip switches. I assume that the screw on the back of the angle drive doesn't provide calibration does it? stephen Edited by - stephen grant on 12 Apr 2008 21:53:05 Link to comment Share on other sites More sharing options...
Frying Pan Posted April 12, 2008 Share Posted April 12, 2008 Stephen IIRC, there is a rubber grommet on the back of the speedo - the DIP switches are beneath this. Guy -----See some pictures of the build here. 13000 miles completed! Link to comment Share on other sites More sharing options...
w7rren Posted April 13, 2008 Share Posted April 13, 2008 ( May depend on how many dip switches you have ) I seem to remember that this calibration table helped me out, I ended up altering the switches & then checking with gps till I got it right. It took a while but success in the end edit ---- I see that you have no dip switches so ignore this Edited by - w7rren on 13 Apr 2008 09:24:25 Link to comment Share on other sites More sharing options...
stephen grant Posted April 13, 2008 Author Share Posted April 13, 2008 Yep, no sign of dip switches for me. I think I shall revert back to the old angle drive and see if that makes a difference... s Link to comment Share on other sites More sharing options...
grumpy the 7th Posted April 17, 2008 Share Posted April 17, 2008 Have you changed road wheel sizes???? that makes a difference (but 25%+ seems excessive unless you've put 10" mini wheels on 😬) rog C7 TNT - it's Dynamite!(Honda Irish Green and Peugeot Graphite grey) Link to comment Share on other sites More sharing options...
stephen grant Posted April 17, 2008 Author Share Posted April 17, 2008 No, same wheels, although I suppose if I had gone from 16" down to 13" or something like that I might have got such an effect. Got the day booked off work tommorrow to do some spannering, so I'll take another look then. Logic tells me it can only be the speedo or - a very outside possibility - the new angle drive. I'll switch back to the original angle drive in the morning and if that doesn't put it back to how it used to be, then the speedo must have gone nuts... There are a couple of screws on the back of the speedo, but I'm not brave enough to go in there; I have visions of springs and cogs flying out in all directions. stephen Link to comment Share on other sites More sharing options...
luddites7 Posted April 19, 2008 Share Posted April 19, 2008 Have finally got the car back on the road and managed to get out in it during rain clouds - Speedo now appears to be working. After reading Daves response I spoke with redline components and they sent me a longer interconnecting quill. I ground 5 mm off the end going into gearbox and it sits in really nice now and doesnt spin in the angle drive anymore. Would suggest anyone changing the angle drive make sure they ask for the longer quill as the short one is causing the intermitant problems. Just need some decent weather now. Jas Link to comment Share on other sites More sharing options...
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