Regarding the posting about low humidity, it was two years after
moving to the desert before the upright Ampico showed signs of wood
shrinkage.  The two large bolts at either end of the stack were loose
by more than a half-turn.  You could hear the rush of air entering
the stack.

Tightening the bolts did not fully restore the functioning of the
Ampico, but allowed it to play.  The bolts are now loaded with a
compression spring.  All the usual precautions were observed in its
rebuild except for running a liquid filler through the stack to seal
its insides.  I suspect that the pump itself may have some leaks or
curled flap valves.

Bill Chapman
La Quinta, Calif.