I've been staring at this clutch fork all week and I'm trying to understand what happens when the clutch pedal is pushed. It looks like the throw out bearing is pulled aft, towards the transmission. If this is true, how does the diaphragm spring "invert" and push the pressure plate away from the disc? Am I over thinking this?

 

The flywheel and pressure plate are bolted to the engine (crank shaft) and the clutch disk is connected to the transmission on the splines. The clutch is compressed between the fly and pressure plate by the finger springs on the pressure plate. When you push the clutch pedal in it pulls the springs back on the pressure plate allowing the clutch disk to spin independent of the flywheel and pressure plate.

 

I get all that. But the pulling of the center of the diaphragm towards the transmission makes the perimeter (pressure plate) move towards the flywheel, essentially holding even tighter.
Maybe I'm not understanding the spring action.

 

The pressure plate disc moves back and forth slightly on the spring inside the housing part. It is held against the inside part of the spring. Here is my pressure plate:

 

This should clear things up...

 

The answer lies in the fulcrum/lever geometry, whatever that may be.

I've never directly handled a 996/997 clutch assembly, but I'm used to designs that look like this:



Ours must have the fulcrum and PP contact points reversed, so that TOB moving out (rather than in), disengages the clutch.