geordieggg Posted February 8, 2007 Share Posted February 8, 2007 I recently installed a new clutch (stock replacement) in the car, and it's now starting to show the same symptoms as the old one I replaced. The old clutch used to slip at high rev changes, then got to the stage where even just trying to accelerate up the hill would cause it to slip. Bought a new clutch kit with everything, had the flywheel machined and the thrust bearing changed over by a shop. The problem I ran into was that the slave cylinder initially didn't want to mount up, it was like it was trying to constantly engage the clutch. I checked the slave was working correctly (not seized at all) but never thought of checking the pivot inside the bell-housing. Ended up having to shorten the rod, which seemed to work ok. Now however I'm starting to run into the same problem as what caused me to change the clutch in the first place, and I'm wondering if it's the pivot causing problems. The pivot itself was in good condition, it just "looked" like it was sitting quite a way out. The question I have is, what affect does adjusting this pivot have? My understanding is that, if it's further out (closer to the flywheel when the gearbox is installed) it'll move the end of the fork that contacts the slave closer to the front of the car, and if this happens on a large enough scale, the thrust bearing will always be in contact (however minimal contact it may be) with the clutch fingers. The other problem it may cause is the angle between the fork and the collar may be too great, causing the collar to bind on the shaft. Is my understanding correct? If so it seems logical to drop the box, move the pivot, replace the now shortened rod from teh slave cylinder and go from there. Quote Link to comment Share on other sites More sharing options...
evildky Posted February 10, 2007 Share Posted February 10, 2007 first of all, you need to tell us what model of trans you are running, the early cars used an external return spring and smaller diameter slave cylinder with adjustable pushrod, is the pushrod clevis adjusted properly? which throwout bearing collar are you using? they came in 3 sizes, and are not interchangalbe, if your throw out bearing is resting against the tines of the pressure plate it's not gonna work, and what clutch are you running, a lot of us have had issues with CM DF's Quote Link to comment Share on other sites More sharing options...
evildky Posted February 10, 2007 Share Posted February 10, 2007 and oh yeah, if you're cutting the pushrod you are definitely addressing the problem wrong, I had my trans in and out of my car at least a dozen times lat time I did a cltuch for what turned out to be a bad pressure plate, my record is 23 minutes Quote Link to comment Share on other sites More sharing options...
geordieggg Posted February 10, 2007 Author Share Posted February 10, 2007 .....last time I did a clutch for what turned out to be a bad pressure plate, my record is 23 minutes Might be quicker for you to fly over here and pull my box out than me doing it myself!! hahaha I have no idea what box it actually is, as the whole car is a bitsa (thanks to the PO). It does have LD20 written on it, so I'm assuming it's out of something else. However it doesn't have any external spring, and the pushrod on the slave cyl. is non-adjustable. Clutch cover was the same height as the one I removed, and is just a standard OEM replacement clutch I have no idea what collar I'm using either, but will check this (and the box number) when I pull it out again. I understand that cutting the rod was not the way to fix it, but needed the car going and driveable for a short time, and I have another slave & rod there. Now I've got a little more time I can fix it properly. I'm pretty sure I've got another collar there as well, so will hunt that down and compare them. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 11, 2007 Share Posted February 11, 2007 I had the same problem with my 73z. The linkage that pushes the master cylinder had come loose and tightened the adjustment. This pushed the slave cylinder slightly out, which in turn causes the clutch to not fully engage. I was also fighting thrust bearing problems in the engine as well. If your slave cylinder is tough to put in, then this is your problem with the slipping clutch. To fix it, check that asjustment and see if it is way out. Quote Link to comment Share on other sites More sharing options...
geordieggg Posted February 12, 2007 Author Share Posted February 12, 2007 The linkage that .........asjustment and see if it is way out. First thing I checked yesterday, it seems all good. which throwout bearing collar are you using? they came in 3 sizes, and are not interchangalbe, if your throw out bearing is resting against the tines of the pressure plate it's not gonna work Had to pull the motor out last night so thought it'd be easier to pull the motor and fix the clutch with it out rather than fixing what I need to on the motor and then pulling the box. I'll be checking for measurements, but I'd say that the collar is too long, or the clutch cover is too big (apparently the three different collars are to match three different clutch cover heights??), or both, so I'll get it sorted eventually. thanks for theinput so far guys. Will elt you know how I get on. Quote Link to comment Share on other sites More sharing options...
geordieggg Posted February 12, 2007 Author Share Posted February 12, 2007 Right, so here's the problem as I understand it: New clutch cover was same height as the one I removed from the car. Now, I have one I removed from a R30 Skyline as well, so I thought I'd check that. Old Skyline cover height = approx. 44mm Thrust bearing collar from same clutch (measured to face of bearing) = approx. 58mm Which gives a total of 102mm from flywheel, plus a little more for clearance. Now, the new one I got has: New cover height = approx. 58mm Thrust bearing collar from same clutch (measured to face of bearing) = approx. 58mm Which gives a total of 116mm - too much right? Which leaves me with a problem. It looks like I need a collar that is about 46mm (measured to face of bearing). Does that sound about right, or have I missed something major? Quote Link to comment Share on other sites More sharing options...
cpt jack Posted February 16, 2007 Share Posted February 16, 2007 and oh yeah, if you're cutting the pushrod you are definitely addressing the problem wrong, I had my trans in and out of my car at least a dozen times lat time I did a cltuch for what turned out to be a bad pressure plate, my record is 23 minutes hahahah dammit well i have the fastest in my school i pulled my tranny replaced the clutch fork and made a push pin for the slave and reinstalled everything and fluids with in and hr and 20 min lol..... Quote Link to comment Share on other sites More sharing options...
Guest hi11i3r Posted February 22, 2007 Share Posted February 22, 2007 Before you impress everyone with your speed at pulling the gearbox out, have you checked the pedal adjustment? Quote Link to comment Share on other sites More sharing options...
geordieggg Posted February 26, 2007 Author Share Posted February 26, 2007 Before you impress everyone with your speed at pulling the gearbox out, have you checked the pedal adjustment? Yeah checked that right back at the start of the problems. Ended up having to pull the motor out anyway (thanks to a snapped bolt) so measured absolutely everything and came up with the conclusion that the cover sat too far back from the flywheel, so swapped it with another one I had from my other car. Problem solved. Quote Link to comment Share on other sites More sharing options...
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