'89 100 clutch sticking

[Eyvind Spangen]

A friend of mine has got an '89 100 (non-q) with clutch problems. 
Sometimes the clutch pedal stays at the floor and the clutch operates
as it was released. The pedal comes back up by itself in about 30
minutes. There is no loss of brake fluid. Both the clutch slave and
master has recently been changed. I'm thinking that air is trapped
somewhere in the system, any other tips?

-- 
ES