After driving a friend's RX-8 (with 35K miles), I noticed that my clutch engagement point is noticeably higher. I also noticed that recently (with wear on my clutch?) the friction "area" itself is taking longer to become full engaged (from the point that the clutch is starting to engage to full engagement).
I dug up the service manual stuff related to clutch pedal adjustment and it specifies the following specs:
clutch pedal stroke: 5.12"
clutch disengagement pedal stroke: 4.402" from the top (.718" from the floor)
clutch free play: .20"-.59" ("until clutch resistance is felt")
I measured my pedal tonight and my measurements are:
clutch pedal stroke: 5.31" (0.19" over spec)
clutch disengagement pedal stroke: 3.875" from the top (0.53" under the spec) (1.4375" from the floor, 0.72" over the spec
clutch free play: ~1" (about .4" over the spec)
So.. it seems like I'm in a no-win situation here: if I adjust the rod (10mm bolt) to extend towards the clutch pedal (away from the firewall), I will lower the disengagement point, but then I will also increase clutch free play (which is already too much). If I adjust the piston rod the other way (towards the firewall), to reduce the clutch play, I will end up with an even higher engagement point.
That is, if I adjust the piston rod such that the clutch engages .72" from the floor, the I will have increased my free play to 1.72"! That's, like, a lot of free play.
Now, if I adjust the pedal stroke to lower the pedal by .19", then I will reduce my free play by .19". But what will this do to the clutch engagement point? It seems that it would shorten the clutch disengagement "stroke" from the top and keep the stroke from the floor the same. If I then adjust the piston rod to be closer to increase clutch free play back to 1", then I will gain a .19" lower engagement point, just a minor difference.
So am I SOL here or am I confusing something?