allenforster Posted February 14, 2011 Report Share Posted February 14, 2011 I have been chasing my dragging clutch problem round the system, and still don't seem to have cured it. With the clutch depressed sometimes I can shift into reverse and first without a crunch, and sometimes not (in fact sometimes have to switch off to engage any gear). Dragging clutch is not enough to move the car, in fact when one wheel is jacked up and the clutch depressed (in gear) fully it spins slowly, but can easilly be stopped by hand. About 12 months ago I changed the clutch in it's entirity, and the operating lever, and the fulcrum. The problem was there before and after. I have replaced the crankshaft thrust washers to eliminate end float - a bit better but not cured. I removed the master cylinder on Saturday and it all seems pretty good, there is some play on the push rod, but that looks like it is designed in. There is also some wear on the clutch pedal where clevis pin goes and on the corresponding forked end of the push rod. Does anyone know how sensitive the system is to wear in this area? Thanks to all the experts out there as always. Quote Link to post Share on other sites
David James Posted February 14, 2011 Report Share Posted February 14, 2011 Hi - It sounds like you need to find out whether the problem is within the hydralic system or the clutch operation itself. Does the clutch feel normal and consistent each time it is depressed? Does the slave cylinder rod move the operating fork end a sufficient amount and hold its position whilst the pedal remains down? If the fork appears top move correctly then the problem will be within the mechanical side of the clutch. Did the clutch plate slide freely on the gearbox input shaft on assembly? Are the clutch components correct and in serviceable condition? I am sure others may be able to add other points to look for.Hope this helps. Good luck. David Quote Link to post Share on other sites
JohnMV8 Posted February 28, 2011 Report Share Posted February 28, 2011 If the clutch worked OK at one time I would think it would be a hydraulic problem. Its worth looking at this before taking the car apart to check any mechanical problems. I had a similar problem some time ago, but possibly not quite the same - I didn't carry out a through investigation, and used a repair kit on the master cylinder which worked - for a while and then failed again. It was finally and reliably cured by replacing the master cylinder. The aluminum bore on the old master had just worn out. I still have the new master cylinder but not the car. It is available (apologies for the blatant advertising)in the for sale section if you are interested. Also you might need to check the slave cylinder. I used a repair kit on mine which seemed to work OK. Also any flexible hoses will need checking for balooning. I assume that there are no leaks. Quote Link to post Share on other sites
allenforster Posted February 28, 2011 Author Report Share Posted February 28, 2011 Thanks for your thoughts and suggestions. I have removed and refurbished the clutch master cylinder (perhaps I should have replaced) and I am going to fit a new hose - probably a reinforced one. I suppose I should really take off the slave cylinder and have a look at that whilst it's in bits - I hate to disturb the (ridiculous) push rod mechanism though. Knowing my luck it will become disconnected when I take off the slave cylinder and then I'll have to drop the gearbox. Quote Link to post Share on other sites
tr7jim Posted March 1, 2011 Report Share Posted March 1, 2011 Allen, I agree its the hydraulic need beeding again, but do think you need to replace the slave cylinder. I had the same problem with my TR7 Sprint and was only cured when I replaced the slave cylinder. Quote Link to post Share on other sites
TR8IAN Posted March 1, 2011 Report Share Posted March 1, 2011 Hi Allen, I think it's certainly worth going with Jim's suggestion of one more bleeding session. If that comes to nothing I think you are going to have to look at the slave cylinder ( I have never broken the plastic clip on the push rod but certainly take care). Having gone onto braided metal clutch pipe I woudn't go back to the old plastic pipe system. Cheers Ian Quote Link to post Share on other sites
John390 Posted March 2, 2011 Report Share Posted March 2, 2011 (edited) Why has nobody suggested the gearbox? All my TR7,s and TR8 all have gear change problems and I put that down to knackered gearboxes. Either general wear and tear or even oil problems. I have never bothered to investigate. One day perhaps? Cheers John Edited March 2, 2011 by John390 Quote Link to post Share on other sites
allenforster Posted March 2, 2011 Author Report Share Posted March 2, 2011 Gentlemen, Thank you for your reassurance and encouragement. I will risk taking off the slave cylinder (and be very careful) and I will purchase a braided hose at Stoneleigh on Sunday. Quote Link to post Share on other sites
TR8IAN Posted March 2, 2011 Report Share Posted March 2, 2011 Allen Are the hose people next to the office no good - get them to copy your plastic one with the correct bends and end fittings. Cheers Ian Quote Link to post Share on other sites
allenforster Posted March 3, 2011 Author Report Share Posted March 3, 2011 I showed them the original 'plastic' Girling one and their advice was that it would not need changing. However having taken advice from TR owners I think that I'll risk squandering the £35 or so. Quote Link to post Share on other sites
Guest ntc Posted March 3, 2011 Report Share Posted March 3, 2011 There is also some wear on the clutch pedal where clevis pin goes and on the corresponding forked end of the push rod. Does anyone know how sensitive the system is to wear in this area? Thanks to all the experts out there as always. Allen I asked somebody on your behalf and was told yes very sensitive,so I would look there first Quote Link to post Share on other sites
Ian Mould Posted March 8, 2011 Report Share Posted March 8, 2011 Hi I changed the master and slave cylinder on the clutch last weekend. The car had been unused for over a year and refused to go into gear. The circlip in the master cylinder seemed to have disolved so I couldn't dismantle it. I declided to change both. Slave cylinder came off easily - just two bolts. I left the push rod well alone due to the horror stories of having to take out the gearbox if the mechanism becomes dislodged. Works fine now. Just need to stop the oil leaking out of the camshaft cover and take it for an MOT! Good luck Ian M Quote Link to post Share on other sites
chris turner Posted March 10, 2011 Report Share Posted March 10, 2011 Whilst the clutch was out did you inspect the spigot bush/ bearing in the end of the crankshaft, if that is worn it can cause the clutch to drag a little. Quote Link to post Share on other sites
allenforster Posted March 11, 2011 Author Report Share Posted March 11, 2011 I stripped the slave cylinder down last weekend and the bore of the cylinder not swept by the piston was really cruddy. I should have bought a new one at Stoneleigh but was too tight! Hopefully I'll have time to clean it up and refit (with new seals) on Saturday. Quote Link to post Share on other sites
Alec Pringle Posted March 11, 2011 Report Share Posted March 11, 2011 Hi Allen, I've been down this road . . . . if the unswept bore is cruddy then the swept area will have been degraded. Kitting the cylinder is a temporary solution only - fine to keep a seal set in the long distance touring kit in the boot. It'll get you home in emergency, as long as you can pump up enough to engage gear from stationary, you can live without a clutch on the move. But if you have the access at home, change the slave and be done with it. Otherwise you'll be doing it again before mid-summer. Cheers, Alec Quote Link to post Share on other sites
tr7jim Posted March 12, 2011 Report Share Posted March 12, 2011 Allen, That was the same issue with my TR7 Sprint and as been ok since I replace the slave, I was more lucky with the master cylinder which was fitted with a stainless steel sleeve so the kit worked fine. Quote Link to post Share on other sites
allenforster Posted March 14, 2011 Author Report Share Posted March 14, 2011 Well I fitted new seals to the slave cylinder and absolutely certain of success refitted it to the car. As you might expect my confidence was misplaced, no real difference! I can get forward gears but clutch not disengaging enough to get reverse with the engine running. The slave cylinder was pretty horrible so following Alec's advice I will change it before I pull the box off (again)- just to make sure. On the plus side I am now really familiar with the operation of the TR7 clutch hydraulic system! Quote Link to post Share on other sites
The Wedge Shop Posted March 23, 2011 Report Share Posted March 23, 2011 Well I fitted new seals to the slave cylinder and absolutely certain of success refitted it to the car. As you might expect my confidence was misplaced, no real difference! I can get forward gears but clutch not disengaging enough to get reverse with the engine running. The slave cylinder was pretty horrible so following Alec's advice I will change it before I pull the box off (again)- just to make sure. On the plus side I am now really familiar with the operation of the TR7 clutch hydraulic system! Allen, I know this sounds silly, but with the car running and out of gear, pump the clutch pedal for a few minutes (yes a few minutes) and see if it comes back to life. We see this from time to time and pumping the pedal consistently for an extended period of time seems to resolve the issue. let me know Thanks Clint The Wedge Shop www.thewedgeshop.com Quote Link to post Share on other sites
Guest ntc Posted March 31, 2011 Report Share Posted March 31, 2011 Have you bleed it right? to save time http://www.mossmotors.com/sitegraphics/pages/mosstv/mosstv_featured.html Quote Link to post Share on other sites
allenforster Posted April 20, 2011 Author Report Share Posted April 20, 2011 Thanks Ian, You were right I have had the slave cylinder on and off about a dozen times now without disturbing the plastic clip. I need not have worried. I replaced the slave cylinder and bled it about six different ways - much better results when detached from the bell housing (thanks NTC). I also tried pumping the clutch for several minutes as suggested by the wedge shop. Unhappily the clutch still drags though, if I get time over the weekend and the sun is shining I'll pull the gearbox off. Quote Link to post Share on other sites
allenforster Posted June 29, 2011 Author Report Share Posted June 29, 2011 Well after months of problems I now have the 7 back on the road. The prize I think goes to Stuart, though it's a bit difficult to be sure as whilst the box was off I replaced everything(again). However, I did not replace the spigot bush the first time round, and when I inspected it there was about 1.5mm play. I could also see witness marks where the gearbox input shaft had been touching the spigot bush retaining plate. Thanks to all for helping me get through it (I have my fingers crossed and I'm touching wood)! Quote Link to post Share on other sites
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