Well, I'll be dipped in sh!t and rolled in the hay... Dammit, JP, it's too bad you didn't come by and notice my note for you on the seat of my car!
I had the IDENTICAL problem at the fling on Saturday. After a hot day of Columbus city driving and a couple of hard 2nd gear launches Friday night, I noticed, on the way to the Speedway station, that I could induce clutch slippage in 3rd or 4th gears and that I had no clutch free play. It was as if something had become bigger rather than worn smaller. My first thought was that I must've boiled the clutch fluid and a bubble was preventing the clutch from engaging fully, so I bled the clutch at the Speedway. No change. In London, I loosened the bracket which holds the slave cylinder to the block, allowing the cylinder to cock forward a bit and getting me enough free play to limp back to the hotel. On the way back to the hotel from London, I stopped and bought a hacksaw and a piece of 1x2, then, back at the Fairfield, Tom Walega (Thanks again, Tom!) and I blocked the clutch in the disengaged position, dropped out the operating rod and cut it about 3/8" shorter. Not having any other way to round the end, we decided to practice third-world auto mechanics and took turns rubbing the rod on the concrete. We had it about half done when a fellow Cobra owner (big thanks to the guy in the red FFR also!) brought us a file on his way back from getting dinner. We replaced the operating rod, adjusted the clutch and everything worked fine for the approximately 500 miles home.
So... we cured the symptoms but what the heck is the disease??? I've never experienced a clutch which gets tighter rather than looser. I suppose something might be wrong inside the bellhousing, but, aside from the above, the clutch behaved no differently from before, and now it's the same as when it was new. No chattering, no clunking; nothing. Is it possible that the slave piston or master piston suddenly stopped retracting fully into the cylinder bore? I don't think break-in has anything to do with this problem. This is a Centerforce clutch. My clutch (and motor) was broken in like a baby and, while I've drag raced it on several occasions, this clutch in a car this light is probably loafing 99% of the time. I agee that slippage would not be as noticeable in first or second gear because, with the lower overall gear ratio, the clutch doesn't have to work as hard. Also, since revs build faster in the lower gears, you don't have as much time to notice the slippage.
Eric: I haven't replaced any rear tires, either.
So... what the heck here? Why would a heavy duty clutch, properly broken in suddenly need to be adjusted for MORE free play, with NO other detectable changes?
And, for any of you undecided guys reading this thread, had this been a big block motor, accessing the the clutch slave cylinder from the top would have been impossible, even for a guy with my long skinny arms.
Lowell