exlifesaver Posted March 11, 2016 Share Posted March 11, 2016 Having a problem with stock clutch master cylinder pushing the pin of the stock RB25 transmission slave cylinder the max. Interesting in knowing if anyone has had this problem and a cure may be a larger bore cylinder? Quote Link to comment Share on other sites More sharing options...
exlifesaver Posted March 11, 2016 Author Share Posted March 11, 2016 The car is a 1971 240z Rb26 swap Quote Link to comment Share on other sites More sharing options...
TimZ Posted March 11, 2016 Share Posted March 11, 2016 The car is a 1971 240z Rb26 swap Can't answer swap specifics, but this Wilwood part is a direct bolt-in (mostly). You can swap the stock pushrod into it, and if you add a 1/8npt 90deg street elbow and a 1/8npt to 10mm inverted flare adapter, the stock line even comes out in the right place. http://www.wilwood.com/MasterCylinders/MasterCylinderList.aspx?group=Compact%20Remote%20Flange%20Mt%20Master%20Cyl-1/8%20NPT%20Outlet Here's a couple of related posts: http://forums.hybridz.org/topic/122481-wilwood-compact-clutch-master-cylinder-no-260-10374/?hl=%2Bwilwood+%2Bclutch http://forums.hybridz.org/topic/94004-easy-clutch-master-swap/?hl=%2Bwilwood+%2Bclutch (different master cylinder, but the pushrod swap is the same) Quote Link to comment Share on other sites More sharing options...
mtnickel Posted March 11, 2016 Share Posted March 11, 2016 Having a problem with stock clutch master cylinder pushing the pin of the stock RB25 transmission slave cylinder the max. Interesting in knowing if anyone has had this problem and a cure may be a larger bore cylinder? I have this problem as well, BUT I also have a different slave cylinder. From other posts, people have said a certain year corolla one works (AE71?). I went with that, and I have the same problem. It is however a 13/16" slave. The stock RB25 slave was 3/4". I have ordered the original RB25 slave and will see if that helps the travel problem. I could drive the car with the 13/16, but there was no dead zone at the bottom of travel even with all the slack taken out. Interestingly, the Nismo Spec slave is 13/16" as well to decrease pedal effort. Perhaps it requires the nismo slave as well, or it's expected that the performance clutches have less actual throw. Let me know how you make out with the issue. Make sure you you have the oem 3/4" slave. From my reading and searching, the RB25 had the same diameter master cylinder as the S30, so it shouldn't be an issue. Mark Quote Link to comment Share on other sites More sharing options...
exlifesaver Posted March 11, 2016 Author Share Posted March 11, 2016 Thank you also Mark As soon as I figure out the right combination I'll definitely get back to this thread But really appreciate all the imput you all have given me. Quote Link to comment Share on other sites More sharing options...
mtnickel Posted March 11, 2016 Share Posted March 11, 2016 I have this problem as well, BUT I also have a different slave cylinder. From other posts, people have said a certain year corolla one works (AE71?). I went with that, and I have the same problem. It is however a 13/16" slave. The stock RB25 slave was 3/4". I have ordered the original RB25 slave and will see if that helps the travel problem. I could drive the car with the 13/16, but there was no dead zone at the bottom of travel even with all the slack taken out. Interestingly, the Nismo Spec slave is 13/16" as well to decrease pedal effort. Perhaps it requires the nismo slave as well, or it's expected that the performance clutches have less actual throw. Let me know how you make out with the issue. Make sure you you have the oem 3/4" slave. From my reading and searching, the RB25 had the same diameter master cylinder as the S30, so it shouldn't be an issue. Mark Note as well that a smaller slave results in more travel. Opposite effect from a smaller master. Probably known, but thought I'd make sure it's understood. Quote Link to comment Share on other sites More sharing options...
Klmykvl Posted March 12, 2016 Share Posted March 12, 2016 Please keep us updated on a combination that works. I'm going to be going RB soon and would like to know. Quote Link to comment Share on other sites More sharing options...
exlifesaver Posted March 27, 2016 Author Share Posted March 27, 2016 Thanks for all halls help guys! Ended up there was no problem with with the hydraulic system at all. We had a "stuck clutch disc", first time I've ever heard or had this problem. That being said the factory 5/8 clutch master cylinder will work the factory 3/4 rb25 slave cylinder just fine. And if you ever have a stuck clutch disc, do this.. 1. Put the car in 4th gear and pull up the e brake 2. Push the clutch in and try to start the car. 3. Hopefully the starter had enough torque to break the clutch disc free from the flywheel or pressure plate. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 28, 2016 Share Posted March 28, 2016 Given how hydraulics work, stroke out is a function of stroke in and my recollection was bores were very close on RB and S30 diameters. Your revaluation confirmed what I thought. Thanks for posting what you found! It's what I suspected but without the bore size differential I couldn't do the calls to check... Quote Link to comment Share on other sites More sharing options...
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