1. Lift up the tap/capstan (that's the bit that spins) if it comes off then the screw holding it on the tap spindle has come off.
2. Pop out the centre cap to reveal the screw simply replace if it has come out screw back down on to the spindle not too tight.
3. If tap won't come off pop the centre cap if screw still in place unscrew and seek source of replacement cap as either the spline had worn in the tap/capstan or on the tap spindle.
Bob, June 2011
