Great to be a part of Classic Zcar Club. I have built/restored/modified my classic Z with little or no help. I need help now. I keep blowing my slave cylinder out and believe that the retaining clutch springs are weak and alowing the fork to move and therefore slave cylinder piston comes out to far? If this is the case, do i have to drop the trans to replace? Any help would be awesome. Cheers

You might have a thin collar on a thin pressure plate. Some have just built a new longer rod and used that although that could create other problems.

What kind of car and engine?

Thanks for the reply Zed. 1974 Datsun 260Z. My z has about 30miles in the last 4 years, not much drive time. What a shame, i know. Well this is the second time i have had this problem since i have owned her. I can assure you that the pressure plate and the rest is 100% but not sure about the small items such as the retaining springs and clutch fork? I just want to drive. Help me..

Hey Chefman,

Welcome! I assume you mean you are pushing the piston out of the end of your slave cylinder? If you have indeed put in a new clutch pressure plate, you may well have used the wrong sleeve for the through out bearing and not even have known it. If the bearing came as a separate piece and you had to take the old bearing off and put the new bearing on the sleeve, I'd bet a fortune that is the case. If not, something else is amiss. I had to fabricate the rod on my 77 because of this issue. Push the piston all the way into the slave and see if the rod falls off the throw out bearing arm. I'm thinking it does. If it does, you need to build a new one. I used a grade 8 bolt, cut the head off, measured the distance of the short rod as pushed all the way in PLUS the distance of between the end of that rod to where it would set into the arm. You want it just a fuzz shorter, 1/8 or so. I even took a grinder and made the little notch for the rubber sleeve to fit into. It was much easier than pulling the trans back out and locating the other collar. I've been working clutches and bearings for two weekends straight now and it is all pretty fresh. I have some pieces laying in the garage I can take pics of to help exlpain what I think is the matter.

Good luck, let us know,

Leonard

Hello Leonard,

Thanks for the Welcome. I have not replaced the pressure plate or the disk. Sounds like i have a weak pressure plate? I did drop the trans this weekend and everything looked great from what i could tell? I replaced the retaining springs and fork arm bushing and re installed. I could kick my self in the arse if i had it inn me after all that work. I bleed clutch and same happened. I build this z many years ago and has maybe 400 miles on her. when i built her i had this same problem once and never happened again? But now that she is ready for the road again after rewiring the entire car she is doing again? Do you think i should just replace the clutch again and be done with it? Seems like the best thing to do?

Taking the problem to what we called when I was getting educated, "first principles", the slave cylinder should only get pushed all the way out if it is starting from a point close to the end of its cylinder, since it is designed to work with the stroke of the master cylinder. If the slave piston starts from the right spot, the master cylinder can't push it out because it doesn't have the volume (you didn't install a bigger bore master cylinder, did you?). So, for whatever reason, your slave cylinder piston is farther down its bore than it should be. Assuming that nothing is cracking, bent, broken or wearing out, like the clutch fork or collar or pressure plate fingers, then the fix is a longer rod. That will push the slave cylinder piston back up the bore to a new starting spot so that it can get its job done before it pops out.

I believe that the only thing determines the piston's resting point, is the tip of the clutch fork, which is determined by the pressure plate fingers pushing back on the collar, pushing on the fork. Can't say what was happening before, but that seems like the best fix. Worst case, you cause some funky wear on the pressure plate and/or collar but you're thinking of replacing them anyway. It's a "can't lose for trying" effort, I think.

hey guys, just took the z for a spin and everything was great. I sill think i will replace the clutch at this time, sucks to drop the trans again, but must make sure its right? Thanks to everyone for there input. I will keep u guys updateded as what i find? Thanks

Everything is working well on the Z, but going to replace the clutch any way, just to be 100% sure. Anyone have advise on clutch kit to buy? Good/Bad/awesome? Note, within the next year after coil-overs, cage and fuel cell she will go to auto-cross.

Did you change anything? Or did taking apart and putting it back together the same way do the trick?

On the clutch, take note of Blue's recent post on counterfeits, especially if you're thinking about EBay.

I have an OE-style Rhinopac clutch set and it's very smooth and holds my stock engine and 205-70s just fine. Some people like a grabby clutch so that they can chirp the tires. My old Zoom Perfection OE-style clutch set from NAPA would do that but it also had higher pedal pressure and was grabby when it got hot. By OE I mean not a performance clutch, just stock style.

I replace the retaining springs and fork bushing that was cracked and worn in a bad way, which made the fork move all around a lot. Then i purchase another slave and all seems tight, but still think i sould replace clutch as much as i dont want to drop the trans again, but seems like the thing to do. Is dura last from auto zone an ok kit? Ebay for me is a bit ifffy. Thanks