Often I encounter questions from model "A" Ampico owners in regard
to leaks in the pneumatic stack.  Many of these leaks originate with
unit valves.

The cause is expansion and contraction during various levels of
seasonal humidity, combined with no flexibility of the stiff metal
"clamps" (one clamp for two unit valves).

Repeated tightening only makes these problems worse, because the gaskets
eventually become compressed with no more room for expansion.  Adding
more tension eventually will warp or split the unit valve itself and
open laminations where the unit valves are glued together.  In addition,
more tightening of these clamps will eventually cause the rods threaded
into the stack to strip the wood where they are attached and will pull
out of the stack, causing more problems.

I highly recommend that the original stiff metal "clamps" of the Model
"A" action be exchanged for the more pliable Model "B" unit valve
springs, which will allow the gaskets and wood to expand and contract,
causing far less damage than the original stiff metal clamps.  I am
sure the Ampico company discovered this problem and it is the reason
for the development of the more pliable springs that were used for the
later model "B".

The last I knew, these springs are available from Player Piano Co.,
stock number 1852, or from: Robert Streicher, 590 Parkers Glen Rd.,
Shohola, PA 18458-4205, tel.: 1-570-559-7403

When they are installed, they should only be tightened slightly, or
until the spring starts to bend just a little.  A small investment in
these newer "B" springs will save Ampico "A" owners a lot of grief and
solve many problems.

Other causes for unit valve leaks are: Bakelite valve seats that have
become unglued and loose, warped Bakelite seats, rotted valve leather,
porous new leather, splits in the laminated sides of the unit valves,
compressed gaskets, newer gaskets made of a mixture of cork and rubber.
(The rubber gets old and hard and will not compress.)  The list goes on,
but I highly recommend that each unit valve be tested and checked for
leaks before being attached to the stack.

Another place to check for leaks is the ends of the stack where the
three pneumatic tiers are gasketed together and held in place by a long
metal rod screwed to the cast iron bracket.  Often the original cork
gaskets have compressed and should be replaced.  (In my own piano,
I made new gaskets from packing leather.)  Both ends should be tight,
but be careful not to tighten them too much or it could break the metal
casting or long machine screw that holds the layers together.

There is also a rubber washer on the end of this screw that usually is
old, crumbling and in need of replacement.  A suitable rubber
replacement washer can be found at a plumbing supply house, or a new
gasket can be made from leather that will be sufficient.

Bruce Clark