pfenlon Posted February 15, 2017 Report Share Posted February 15, 2017 Chris back to basics are the master and slave cylinder correct units? Has the spinner plate been renovated and is Thicker (Wider) than it would normally be. Is the pressure plate the correct one? to obtain the correct clearance get someone or a tool to hold the clutch pedal fully down, Then by whatever method move the slave cylinder to get the correct amount of travel. best Pete Quote Link to post Share on other sites
Chris59 Posted February 15, 2017 Author Report Share Posted February 15, 2017 Hi Pete, Master, hose, slave, are all new. The master has a bigger bore that the orignal one, to improve slave piston travel, but now I'm not sure if it's doing its job properly. Flywheel have been checked, clutch plate and mechanism are NOS item, so no worries on this side. Believe me, I've tried to many times to move the slave cylinder further when the pedal was fully down, I even tried to bleed at the same time ! I told you, she turns me mad..... Quote Link to post Share on other sites
RogerH Posted February 15, 2017 Report Share Posted February 15, 2017 Hi Chris, a bigger diameter MC will move more fluid for the same piston movement. So, assuming the slave is the standard size, it should move the slave piston further. Roger Quote Link to post Share on other sites
Paul J Posted February 15, 2017 Report Share Posted February 15, 2017 I once had a fractured clutch release fork that lead me a run around for weeks, as the clutch was pressed the crack opened and closed again. Gearbox out 3 times before I found it. Best of luck Chris Paul Quote Link to post Share on other sites
Chris59 Posted February 15, 2017 Author Report Share Posted February 15, 2017 (edited) @ Roger, Yes, that's what could be expect, and the reason why I've bought a master cylinder with a bigger piston, but it don't work, for the moment. Honestly, it doesn't matter if I need to do everything again, but I really need to find why this damned clutch plate can't be free : it's the first time since more than 30 years of work on Triumph, that I didn't solve a problem rapidly. One of my brothers offered me to solve the problem with a can of fuel, but I'd rather try again to find a better solution..... @ Paul, if only ! The clutch fork is new, and in perfect condition. Edited February 15, 2017 by Chris59 Quote Link to post Share on other sites
barkerwilliams Posted February 15, 2017 Report Share Posted February 15, 2017 The slave cylinder piston travel is 7mm when the rod is connected (so, under the pressure of the clutch) and 24 mmm when free Chris, If the clutch lever will move then the slave rod cannot have differing lengths of travel depending on the load, hydraulics don't absorb movement /pressure apart from a miniscule expansion. So there must be air in there somewhere, or, I have heard of a master cylinder where the pressurised fluid leaked back into the reservoir past the seals so that the slave only ever had a few pounds of push before the seals released the pressure. No fluid was ever spilled is that possible in your case? Alan Quote Link to post Share on other sites
Chris59 Posted February 15, 2017 Author Report Share Posted February 15, 2017 Alan, you are absolutly right, I followed the same way who bring me to decide to remove the whole thing from the car : the seals of the master cylinder may release the pressure to early. That's why I'd like to know the pressure needed to press a clutch diaphragm, and bench test every associated components. Quote Link to post Share on other sites
graeme Posted February 15, 2017 Report Share Posted February 15, 2017 Hi Chris, My money is on a faulty master cylinder as Alan describes above. It caused me similar problems on my TR4a. Cheers Graeme Quote Link to post Share on other sites
Steves_TR6 Posted February 15, 2017 Report Share Posted February 15, 2017 I had a tiny crack in a flare at the brake mc on my last car when i bought it. This sucked in air but did not leak fluid. If your mc has a bigger diameter then, provided it has sufficient stroke, it must move more fluid. I think i'd test as Roger suggests, how much fluid does the mc pump, then divide by the piston surface area of the slave equals slave stroke. Its either a mismatch in the ratios of master tomslave or air, surely? Steve Quote Link to post Share on other sites
roy53 Posted February 15, 2017 Report Share Posted February 15, 2017 I had a simlar problem in the summer and did not believe i had air in the system as i had bleed probably a litre of fluid through pushed internals of cylinders fully in and still not enough travel. IT WAS AIR . good luck with yours. ROY Quote Link to post Share on other sites
Chris59 Posted February 16, 2017 Author Report Share Posted February 16, 2017 (edited) Well, well, well....... I've decide to remove everything again this morning : gearbox out, to find that the clutch fork and bearing carrier wheren't new, senior moment I guess. They weren't bad neither, far from this, so the problem is not here. Whatever, as the 'box is out, I'll replace the slightly tired cross shaft bushes, they cost nothing. Using an original, new master cylinder and a new slave cylinder (good repro), I tried to bleed them with my home made flexible, once assembled on my bench : it was really very hard to bleed, but, at the end, the result was that, with no more air at all in the system, I was able to push the master cylinder rod, a bit more than I should. Hose expansion, or fluid going back to the reservoir, I still don't know whre the problem is : the best thing to do will be to buy a Goodridge braided hose, and try again ! Edited February 16, 2017 by Chris59 Quote Link to post Share on other sites
RogerH Posted February 16, 2017 Report Share Posted February 16, 2017 Chris, whilst the GB is out have a look at the steel casting that the bearing carrier slides on. Last year I found the splined shaft of the GB and the sleeve the carrier slides on were not concentric by more than 0.015". In my case it caused the whole clutch assembly to judder on releasing the pedal. I found witness marks on the steel sleeve to show where the carrier was digging in. They were only apprx 0.001" deep but caused the problem. This shouldn't affect the bleeding process though. Roger Quote Link to post Share on other sites
Guest ntc Posted February 16, 2017 Report Share Posted February 16, 2017 Well, well, well....... I've decide to remove everything again this morning : gearbox out, to find that the clutch fork and bearing carrier wheren't new, senior moment I guess. They weren't bad neither, far from this, so the problem is not here. Glad you found it Chris but put what I posted in the memory bank Quote Link to post Share on other sites
Chris59 Posted February 16, 2017 Author Report Share Posted February 16, 2017 Will do both mates ! Now, I won't touch this car anymore before next week : a Spitfire and a pair of TR6 need some TLC tomorrow...... Hope to meet fellow forum members this Sunday, is there any "forum meet" expected ? Quote Link to post Share on other sites
Chris59 Posted February 22, 2017 Author Report Share Posted February 22, 2017 (edited) Hello guys, Problem finally solved, and I learned a lesson : do not rely on what you see. The problem was the flexible hose, expendng excessively on its entire lengh (rather important, as it's a lhd Stag and the slave cylinder is at the bottom right of the clutch housing....) : I use this kind of flexible hose since decades, but it seems that this perticular one wasn't correponding to my needs, even if the references stamped on the rubber where telling that it could do the job...... Now, all I have to do is to reassemble everything together, but I'm very happy to have a finally working clutch ! Edited February 22, 2017 by Chris59 Quote Link to post Share on other sites
Hamish Posted February 22, 2017 Report Share Posted February 22, 2017 Well done Chris. Satisfying to get I solved I should think and a relief. Sorted !! Quote Link to post Share on other sites
TR 2100 Posted February 23, 2017 Report Share Posted February 23, 2017 Chris - Good that you have identified the problem and reported back. There will probably be another time, for another owner, so we can add your experience to the list of potential problems. AlanR Quote Link to post Share on other sites
Marc R Posted February 23, 2017 Report Share Posted February 23, 2017 Well done JC... what a situation and thanks' for the feedback Regards Quote Link to post Share on other sites
Chris59 Posted February 25, 2017 Author Report Share Posted February 25, 2017 (edited) Yes guys, you are right, sharing experience is the point of this part of this forum. Edited February 25, 2017 by Chris59 Quote Link to post Share on other sites
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