The Westy front seats do get difficult to turn due to sand and grit in the
tracks.  It is easy to slide the seat out of the forward/aft tracks and
remove the bolts holding those tracks.  Lift off the steel plate and clean
the circular groove and coat with grease.  Replace and it will rotate
easily.  When I did this on my old 84 both seats revolved so well that they
went from side to side about 1/4" as we went around corners!  Go easy on
the grease and do not tighten the hold down blots too tightly.  Use those
bolts to adjust to a satisfactory firmness of rotation.
Don. (90 Syncro "Leana Hula")