Bob Stewart asked about finding Mercury in the pedal regulator of
his upright Ampico B.  Someone probably used a mercury vacuum gauge
on your upright.  I found mercury in the primary valve chest of an
Ampico A concert grand.

Since I believe your upright Ampico B is probably an editor's piano,
and since I know the concert grand where I found mercury was a factory
demonstration piano, I assume the Ampico factory used vacuum measuring
equipment that included mercury.  Failing to keep the manometer upright,
or exceeding the design maximum pressure limits of the devise would
cause the mercury to be drawn into the Ampico system.  The mercury then
pools in the first chamber between the test connection port and the pump.

If the pedal regulator is otherwise normal, the mystery is the mercury,
not the pedal regulator.

Bob Taylor