Questions regarding clutch stroke and bearing carriers

[my_mad_z]

Hello all,

Hoping I can get some advice please? I'm in the process of replacing my clutch and want to make sure I get it right. Sorry if it's a long winded post, tried to keep it short; I have more info but didn't want the post to get longer than it already is.

It's not a standard setup, L28 with an RB25 flywheel and Exedy extra heavy duty clutch; S13 gearbox conversion. Master cylinder is 5/8 and slave cylinder is 11/16. When the clutch pedal is pressed, the slave cylinder has an 18mm stroke which results in the bearing moving about 10-12mm (was hard to measure exactly). Does this sound right or is it not enough travel? I came across a post saying the stroke of the slave cylinder should be 35mm but I'm not entirely sure as I couldn't find this in any of the manuals I have? I've adjusted the MC rod as far as I can, thinking I might need to extend the rod if this travel isn't enough or possibly replace my MC/SC? Neither are leaking and the system has been bled. 

As for the bearing carrier, I'm trying to determine the right one to use; I read on one of the posts that the overall height of the pressure plate and bearing carrier (to the ears/collars) should be 92mm. I'm not so sure this will still apply with the flywheel being off an RB? RB flywheel sits 2mm further into the gearbox compared to the original flywheel. As a test, I took measurements of the diaphragm spring position when bolted on the flywheel. Then with the gearbox out of the car, I setup the reference point in the gearbox of where the bearing meets the diaphragm springs so I could measure the fork position with the different carriers. Got the following:

29mm carrier (flywheel to bearing carrier ears/collars = 83mm):

35mm carrier (flywheel to bearing carrier ears/collars = 88mm):

39mm carrier (flywheel to bearing carrier ears/collars = 92mm):

Correct me if I am wrong but I'm thinking the 35mm carrier is the one to use here? Leaves me with 10mm travel moving away from the pressure plate whereas the 39mm carrier only leaves about 6mm. Didn't have enough hands to hold everything and measure exactly, will try and get a hand to get exact measurements. I'm just concerned that if there isn't enough room for the bearing carrier assembly to move away from the pressure plate, it will hold pressure and cause the clutch to slip. I also want to make sure I have the correct fulcrum for the fork.

I hope I've provided enough info.

Thanks.

Marc.

Edited November 26, 2018 by my_mad_z

[C.A.R.]

If you bolt each one up, how much free-play in the slave pushrod do you get on each one Marc?

[my_mad_z]

Haven't tried it with all combinations; getting too old to get the gearbox in and out From memory, I think the 35mm carrier had between 5-8mm. Not sure if the length of the pushrod is correct? Would be great if I had a standard car I could reference, would make life easier!

[my_mad_z]

How much free play and travel should there be mate? I'm thinking of buying a new master cylinder and 3/4 slave cylinder to try and rule these out.

Edited November 27, 2018 by my_mad_z

[my_mad_z]

I think I've worked out the bearing carrier and fork position; managed to get my hands on a L24 with clutch assembly. Worked out where the diaphragm springs sit and got a measurements of fork position, thrust bearing position and free play. Looks like the 35mm carrier is the one to use with the RB setup, just need to sort out the stroke of the master/slave cylinder now. Hope this works...