Mike,  Your picture shows a "usual" failure mode of the
accordion pneumatics. The pouch leather that it is made from
eventually becomes brittle and some small event causes it to
fail, an event sometimes as simple as touching it to check
for flexibility. (How do I know about that? Don't ask!).

Yes, recovering them does require creating a fixture to hold
the wood "leaves" in proper orientation. Somewhere I have
read about building one, probably in Art Reblitz's book on
Rebuilding the Player Piano.

The hardest thing you will find, if you do it yourself,
is the somewhat large piece of pouch leather it requires.
The other thing is being _very_ careful in applying the glue
(hot hide glue-although in this case one could use the cold
version). You want just enough to hold the leather, but not
so much as to make a ridge on the edge of the boards.

As for the seam, I prefer "Barge Cement" but others may
have other suggestions. (Barge Cement is available at most
Ace Hardware stores, or they can order it. It is a little
expensive, but for leather work it is amazing). Once again,
just a little "dab" will do ya! (I know it's not hair tonic,
and if you get this reference -- how do I say this? --
you're _old!_)

And if you are still unwilling to do it yourself, the nice
thing is that it is small enough to be mailed, if you are
willing to do the final adjustments after installation.
There are, I'm certain, MMDers closer to you to help out
with this project.

David Dewey
Oroville, California