Gus

I have a minor issue with clutch pressure/ volume of fluid pushed by the Master. I have been playing around with the Clutch Master and Slave cylinders to try and reduce pedal pressure and open significant enough volume of fluid to depress the clutch bearing completely. I can get the clutch to disengage with then standard configuration but I have high clutch pedal pressure ( works) . But the disengage point is at the bottom of travel- I have tried a different slave, which reduced pedal pressure but does not completely disengage clutch satisfactory. Slave requires more fluid.
I need to increase the volume of fluid going to the slave to raise the release point on the pedal. I don't see any way of changing setting on the master or clutch pedal mechanicals to do this
Has anyone found a solution to this - different Master - which one??
Looking for a little technical assistance/ advice.IDEAs?/

Rocket Rob

Gus - Have you checked your clutch pedal travel stop and the roll pin? I had a similar problem and in my case, it was a problem with the angle that the clutch pedal was drilled. I'll try to find the thread about it.

Found it - https://rennlist.com/forums/964-foru...ake-pedal.html

Gus

Thanks for the post - but this is not the issue - I have just done a complete rebuild on clutch pedal assembly and replaced the Master and the Slave. Bleed with power bleeder and have driven the car, but the pedal continues to have to be pushed to the floor to get the clutch to release. Have full pedal travel as i have removed the bottom stop and still have same issue - Thanks for feed back. this has always been an issue since I first bought the car - guess I will take all apart again for another look.

FeralComprehension

There's an aftermarket slave (?) from Germany that I remember reading about. Have you seen it?

Bill Verburg

I've never seen anyone need to change from the stock clutch master and slave. Is that what you did?

to work, any hydraulic system need to balance the size of the master and slave against the other operational constraints, like travel and input/output forces.

This is most commonly run into when changing calipers in brake systems or when going from a twin inline master to a dual parallel setup.

Why did you need to go away from stock?

Dan Jacobs

Have you changed the rubber hose?

Gus

Feral - yes, tried the German slave, it is designed to ease pedal pressure but, requires a greater amount of hydro fluid to do so - so made condition worse.
Bill - no change except above which was reversed. My master and slave are OEM. I am wondering if issue is in the GT3 clutch set up I have. Because me disengagement point is so low (floor) I was just thinking that a larger master would move a greater.volume to the slave.
Yes, replaced rubber hose at slave - still feels like there is flex there and am going to replace with stainless .
At this point everything is new - bushings. Pin, master, slave and rubber hose. Pressure bleed, and have rebleed 4 times since. Contact rod to clutch arm has no play.

Bill Verburg

Go w/ whatever Dan J's advice is, he knows way more about these cars than anyone else I know. He did my clutch last year, w/ single mass flywheel and some Gt3 parts but stock clutch master/slave/hose and updated clutch arm, at first it felt hinky but got much better w/ use. Take up is nice and high

Gus

Ok -!waiting for Dan J's comments

Rocket Rob

Gus - When I bought my 91 C2, I was always having problems getting the clutch to fully release. I rebuilt the pedal assembly, replace the hydraulics, clutch, throwout arm. I was getting frustrated. I was kicking myself when we finally found the problem. The original clutch pedal was improperly drilled. My friend had suggested that we disassemble my 90's pedal assembly to compare and I say Nah. What could be wrong with the pedal itself. Doh! In hindsight, I wish we had done a full pedal assembly swap just to eliminate it as a possibility. Do you have any fellow 964's in the area that may let you try this?

Good luck with getting the issue resolved.

Earlydays

Gus, is it possible you have a crimp in the hydraulic line somewhere??

Bill Verburg

When Dan did mine they just replaced the clutch master, slave and hose w/ stock parts and an updated kinematic arm. The issue then was low engagement as you describe. The bearings on the clutch release arm had failed causing this. It needed a new clutch release arm, 997.116.086.90 The clutch disc 996.116.015.32, pp 964.116.028.03 and to bearing 944.116.080.01 were all replaced at the same time.

Gus

Thanks all for info and suggestions - am going back in to check all, if OK will pull trams to check arm and bearing. Will replace river hose with stainless line to see if this helps also.

robt964

I too ordered the 997.116.086.90 when converting to single mass flywheel through my OPC (but received the 997.116.712.9R - another revision?)

This pic shows the difference between the original arm and the later one.

Thread of discovery here

964tit

Oops. I misread OP's post.

Anyway, if anyone is looking for that 'German' slave cylinder:

http://www.mpl-tuning-parts.de/english/porsche.html