[bigmike]

You didn't say, but I'm assuming that you are using a self-contained hydraulic throwout bearing, like a Tilton or Mcleod.
If that is the case, you need to put a pedal stop on your clutch pedal to keep too much of the fluid from the master cylinder from going to the throwout bearing, which pushes it out of its own housing.
You can make a pedal stop by putting a bolt with 2 nuts (for adjustment) through your pedal box or firewall, and adjusting it so that you just get enough movement to feel the clutch fingers over-center.
I have a more detailed info sheet from Tilton, if you need it.

BIGMIKE