John,  The large exhauster pneumatics are usually glued to the central
deck of the steamboat pump without screws.  They are usually glued with
leather gaskets, so they should be fairly readily separated from the
deck at the weaker leather layer, by inserting a thin steel blade such
as a razor blade or thin scraper blade, thin steel cutting wire, or
appropriate prying tools or chisels.

I have usually been able to remove the pneumatics with little or no
damage or splintering of the wooden pneumatic frame.  If the pump has
been previously rebuilt, there is some chance that the pneumatics might
be glued directly to the deck without leather spacers, in which case
removing the pneumatics may be more difficult.

The inner valves of the pump are also mounted on the central deck, so
to avoid damage to the valves it is important not to drive any knife or
cutting tool much deeper than the roughly 3/4" to 1" that is the width
of the exhauster pneumatic frame.

It would be difficult to recover the pneumatics without removing them
from the deck.  Usually, the fabric is both glued and tacked at corners
and edges, and the tacks would be very difficult to remove with the
pneumatics still mounted.  Unless the pneumatics come off very easily
leaving the leather undamaged, it is advisable to scrape the wooden
deck and exhauster pneumatic surfaces smooth, removing the old leather
gasket.  I then glue new leather to the mounting faces of the recovered
pneumatic with hot hide glue, at which point one can usually leak-test
the pneumatic and outer valves by placing it on a flat surface (like a
smooth workbench) and pulling on the upper leaf of the pneumatic, which
should lock to the bench and be quite airtight.  I then apply hide glue
to the deck and clamp the pneumatics gently in opposite side pairs.

Yes, these pumps were beautifully engineered, and they work quietly and
well.  But they were heavy and large, sometimes with only millimeters
of clearance between the stringplate and front cover even in a fairly
large upright.

Ralph Nielsen