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Performance clutch + master/slave cylinder riddle

The part number for the 20,6mm slave should be 8601784. If you're going for an used one I'd recommend measuring the piston to be sure.
E: IIRC both the larger and the smaller slave had FAG S6472G on the casting, but I might be wrong.
 
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h20ham said:
Pushrod length

”The result was that the clutch fork almost maxed out the slave cylinder which was good, because I could use the whole pin travel of the slave cylinder. ”
Click to expand...
Ah, ok. I have put 2 washers under the pivot ball so that the clutch fork came further backwards. This means that it pushes the slave cylinder's pin further "inside" the slave cylinder because it comes closer to it. What does that mean ? It means that i have more slave cylinder travel to use in case i use a master cylinder that will push more fluid in the slave. When the clutch pedal is not depressed i have about 21mm in front of the slave cylinder's piston for it to travel forward. If i remove lets say both of the washers, the piston would move forward and have less than 21mm .. In both cases the piston travel would be the same of course.
 
Acke said:
The part number for the 20,6mm slave should be 8601784. If you're going for an used one I'd recommend measuring the piston to be sure.
E: IIRC both the larger and the smaller slave had FAG S6472G on the casting, but I might be wrong.
Click to expand...
Thanks!! Maybe they sold it officially as a kit (MC+slave combo) ? It could be easy to mix them up if the casting number is the same. It reminds me the oil pump high/standard gears confusion.

Anyway, do you have the part number for the even smaller one 19,05mm and for the one with 22,50mm ?
 
They mention they have a 20,6mm slave and a 19mm master in that thread.
Did you measure how much the pivot point for the arm moved when You swapped to the longer ball nut and added two washers under it? I moved mine about 10 mm towards the engine, no chance to get the clutch working with much less.
 
Acke said:
They mention they have a 20,6mm slave and a 19mm master in that thread.
Did you measure how much the pivot point for the arm moved when You swapped to the longer ball nut and added two washers under it? I moved mine about 10 mm towards the engine, no chance to get the clutch working with much less.
Click to expand...
Unfortunately this was done a long time ago and my memory doesn't serve ! However i know that the clutch fork almost touched the M90's hole end that the fork comes through. I thought of doing that due to the fact that i wanted to be safe, but as it looks i was marginally there. I had also tried 3 washers but it wouldn't fit.

So, i removed the master cylinder today and measured the pedal's movement at the mounting point of the MC and i found out that from end to end is 32mm maybe 33mm. I could grind of course the upper stopping point of the pedal assembly a bit to have my pedal a bit higher if needed and gain some more travel, but i have to get the new MC first and then check this out.

It looks that the "lighter pedal - 0,7 bore MC" goal can not be achieved in my current setup, since it needs 32mm pedal travel, which means that it will engage-disengage right at the firewall which is no good.

So my best bet is this MC:

https://www.wilwood.com/MasterCylinders/MasterCylinderProd?itemno=260-6089

It has a stroke of 34,8mm - bore 19,05mm , dimension wise looks the same, i just need to figure out how to mount it on my pedal, since it does not come with an adapter or something. It has good chance of success since i need around 28mm pedal travel for the clutch to disengage out of the 32mm. And then i can check if i will grind the pedal assembly stop to lift the engaging point a bit further away from the firewall.

Another find was that my MC rod was a bit bent, which means that the pressure of these clutches is probably a bit too much for this pedal assembly. Maybe i got to reinforce the assembly like Dave Barton has done in the past.
 
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