Dear Joe and Group,  many Ampico grands have the sustain pedal and soft
(hammer rail lift) pneumatics mounted inside a box atop the pedal lyre.
The valves for these pneumatics are usually found elsewhere under the
piano.

What could cause sluggish operation?  Were these pneumatics
under-powered to begin with?  No, they weren't, Ampico wouldn't have
kept this design so long without change or modification if that were
so.  So what could be the problem?  I think I know how to help.

Pedal problems are almost guaranteed whenever the piano is moved and
pedal lyre must be removed and reinstalled.  Even experienced piano
movers frequently have trouble putting the lyre back on correctly,
let alone getting the piano on its legs without busting up the drawer.

First check to see whether the tubing from the valves has gotten kinked
or flattened somewhere.  Depending on where the valves are, the tubing
usually has some 90-degree elbows that prevent kinking or prevent the
tube from being pinched slightly, thus restricting airflow.  Some of
the routing of the supply tubes to other components may be hanging up
on the linkage somewhere if the pedal lyre/box has been incorrectly
"stuffed" back into the piano.  Check the mounting bolts: the whole
assembly could be slightly lopsided causing friction.

A less likely but possible source of the problem could be the muffler
felt on top of the valve assembly, usually a grayish color.  This felt
was used to prevent any "chuffing" noise from the airflow through the
valve but if loaded up with dust and tobacco smoke filtrations this
could slow things down too.  It's especially noticeable if the sustain
pedal isn't clearing before raising the damper tray again -- the music
seems "muddy."  A clogged bleed would cause this problem as well.

In my opinion the most likely cause of trouble is the hinge on the
pneumatic itself.  There is a steep bevel on both the front and rear
of the pneumatic where the cloth is affixed/glued.  The cloth must be
glued as follows:  first glue the open (span) and let dry.  Then slit
the cloth on all four corners about 3/4 down before gluing the sides,
glue the cloth to the sides and let dry.  Slit the cloth again before
dragging the excess around for the hinge, _but_ you must glue the cloth
to the backside of the hinge with the pneumatic _closed!_  Otherwise it
will pull the cloth off the hinge and cause a leak (or be hinge-bound
and not close).

Litmus test:  close the pneumatic and block off the supply port.
It should hold the dampers or hammers up, not indefinitely, but the
rate at which they fall is directly proportional to the amount of leak
I suspect is causing the problem.  You should be able to do this
without pulling the whole pedal assembly by removing the four screws
at the top front that hold a black rectangle cover over the two
pneumatics.  (Open the drawer first to see this.)  It could be leaking
through the mounting blocks or whatever other hardware is screwed
into the vacuum chamber of the pneumatic but if it is leaking, it is
probably a recovering error and/or glue failure at the hinge.

Bottom line: something is either kinked or leaking.  The 3/8-inch
supply is sufficient power for lift on each unit provided all else is
correct.  Remember that the hammer lift pneumatic should operate a bit
slow to begin with.  Otherwise the hammers would bobble if it closed
too rapidly.  But the damper lift should have "right now" on/off
operation; otherwise the music is just un-listenable.

Good luck, let us know how it turns out.

Eric Shoemaker