What do you mean by "randomly disengage"? Does the clutch slip or is the
transmission popping out of gear?I can not remember ever hearing of a
pilot bearing failing( I am sure they do though).It sounds like the
clutch is not disengaging. Lie under the car while someone pushes on the
clutch pedal. Watch slave actuate the T/O bearing  arm. Is it rotating 
or is it rotating AND moving away from the slave cylinder? Could be a bad
bushing (long shot). Get a little more info and get back with us.
Drive Safely & Good Luck
Ken Lewis
86 VW Transporter Three Door Pickup
60 Porsche T-5 Coupe

On Mon, 7 Jul 1997 15:26:22 -0500 VWNUT@smus.bc.ca writes:
>
> when the clutch decided to randomly disengage, usually during 3-2 shift
on a 15% uphill grade... I recalled that the pilot bearing had been done
twice 
>by the PO and started pondering just what the heck it does, and why 
>this $6 part could be causing all this annoyance. 
>Anyway, the problem was worst after 1-2 hrs of hard driving it 
>seemed, but we made it another 300+ kms home with little drama aside 
>from a few missed "speed" shifts.
>