I changed my clutch last year to a SOS Sport clutch, after about 1000 miles I start getting clutch slip at full throttle. I put it up on jacks eventually after checking clutch fluid, etc and I Notice that the clutch fork is pretty much resting on the slave cylinder housing, as in the cylinder is fully retracted. Finally one year later i almost a year later I get underneath the car and pull the clutch out, this is what I see:

Part of the ball bearing for the throwout bearing came off

The throwout bearing carved into the clutch disk


Any thoughts on causes? I adjusted the master cylinder as per instructions.

 

I owned the sos clutch kit as well and my clutch lasted me. A whopping 5000 miles... for a $1200 setup i was pissed and wanted to get to the root of the problem. So me and my friend decided to go over everything and after a few moments the issue was obvious. In order to properly run the setup the master cylinder has to be adjusted by the pedal rod. This leads to a major problem. Since nowhere does sos tell you this. Basically if your pedal rod isnt adjusted the pedal with increase in travel due to the difference in the new sos pressure plate. So as the new clutch wears in the pedal travel gets further and further. And all it needs is a few mm to hit fully out. At this point the oil journal inside the slave cant get oil and keeps constant pressure on the plate. Its basically like driving with your foot resting ( heavily might i add ) on your clutch pedal. It will cause glazing, overheating , warping... this will lead to bearing failure and pressure plate failure. Another issue is that at high rpms since the clutch isnt fully engaged it will start to rattle and wobble due to harmonic balancing in turn getting scarred up. The sos clutch with a properly adjusted pedal rod is really really good. But the proper adjustment needed is so fine and precise that it makes it not worth it. Best bet is oem disc and ap1 flywheel with an act hd pressure plate and new oem bearings

 

Just curious...shouldn't the pedal rod Adjustment be varified after any clutch install?

 

Pedal adjustment should be checked on every car. Doing a clutch has no affect on current pedal status.

Looks like you ran the clutch rod too tight. it puts the bearing in full time operation and you likely cooked it, causing it to fail. if it is not repaired, your next clutch will fail also.

You should be able to push on the clutch pedal lightly with your pinky finger, and feel TWO freeplays on an untouched S2000.

The FIRST is play between the rod end and the master piston. LOOK UP UNDER THE DASH and you will clearly see this. you can clearly FEEL it as well.

The SECOND is the short movement of the master piston, before it passes the fluid entry hole from the res and starts to build pressure.

REMOVE THE FIRST freeplay, and leave the second.

Simply loosen the 12mm nut, and turn the rod until it lightly snugs against the master piston. Tighten locknut.

When you are done, LOOK AT THE ROD while applying light pinky pressure. All you should see is the master piston movement (freeplay), and not rod-to-master play. All you should FEEL is one freeplay.

this is the correct setting for every s2k in existence, regardless of clutch setup.

 

I can't really see/understand the difference between those two plays. I loosen the 12mm nut and no matter how much i screw the rod around, I always feel a play. And the rod will always move the same way when I press the pedal no matter how much I screw the rod around.

What is the master piston fluid entry hole ?

"All you should see is the master piston movement (freeplay), and not rod-to-master play"
I don't get this sentence at all. Maybe because my english is not good enough. Some pictures would be really helpfull, explaining where I should have some "freeplay" or "moving" and where not.

@edit: "Rod end" is it the end at the pedal or the end in the cylinder ?

 

this is the best explanation I can provide.

Maybe you are messing with the switch and not the clutch rod?

A pic will not change anything, not in this case.

Fluid entry hole is internal and cannot be seen.

 

Make sure you are looking under the dash at the back of the master with a bright light, before testing the clutch pedal with your pinky finger.

The two different freeplays/movements are extremely obvious.

 

I'm not sure why you are asking about the pedal end or the master end. I really don't know how to be any clearer. Perhaps an interpreter can read this, and re-voice it to you in his words.

 

You are right, "the end where the master cylinder is".. thats actually clear ;P

The problem is, I don't see any play there. With play you mean the rod gets inside/outside the master cylinder without actually pressing the clutch ?

Or do u mean that the rod can be moved sideways (up/left/right/down)?

I know which rod to use and I can either screw it "inside" the clutch pedal or outside. The more "outside" i screw it, the less play I feel (clock wise). I screwed it nearly completely out of the clutch pedal and still feel a little freeplay (which means when I slightly press the clutch pedal I have no resistance for a short clutch pedal travelling way). Maybe this is the "freeplay" that HAS TO be there ?

 

I found the OEM friction disc is a smoother, longer lasting alternative to run with the SOS PP. The friction disc they include is too grabby and easy to get chatter and hot spotting on the flywheel. It just isnt needed to get the trq holding, thats the PP duty. When you wear out the SOS disc, replace it with an OEM and keep the SOS PP

I run mine with a ACT 8.5lb pro light flywheel btw.

I agree, no matter what clutch you install, you should verify and adjust your pedal height/free play, I had to do it a bit with the SOS clutch. This is common practice with any clutch, SOS shouldn’t have to warn you first.