I have three Steinways, all with Steamboat pumps. The two grands have
remote pumps, of course, and one motor is 1150 RPM, the other 1725 rpm.
My upright motor is 1725 rpm.  The intermediate pulley on the upright
pump is slightly smaller than those on the grand pumps.  I think the
late upright bellows may not be as wide as those on the grands.  All
the pulleys on mine are made of cast iron.  Some later pulleys were of
pot-metal and became cracked, swollen, and out-of-round.

Many  grand pumps were later replaced with square rotary pumps.  If a
Steinway grand has a 15-inch pump, it is a conversion from either a
remote pump type or a foot-pumped Metrostyle-Themodist.  People just
didn't like the idea of a remote pump.  So instead, they got a piano
that looked like a pregnant hippopotamus.  The wooden braces under the
soundboard were less than fifteen inches apart; so they had to be
hacked away to fit even a fifteen-inch pump.  Sometimes they didn't put
the pump up all the way up there.  Later Steinway grands had the braces
placed farther apart and received a seventeen-inch pump as original
equipment.

Another reason for converting was that the steamboat pumps often became
terribly inefficient. The earlier pumps had a total of 84 flap valves
backed with thick, dense felt.  A flexible adhesive was used, which
shrunk as it aged and caused the leather valve surface to warp.  As a
result, the pump would move a lot of air around inside without drawing
very much in from the outside, making the pump very  inefficient.  One
of mine would give a static reading of 100 inches without slowing down.
But with the roll-drive motor running at normal speed, the vacuum level
would drop to about half that, and with the spill valve closed too!  In
rebuilding, it is certainly better to glue the heavy felt to the wooden
cross-pieces rather than to the leather.

Unfortunately the original design requires each bellows to generate
more pressure when closing than does a conventional design, with
bellows forms stapled to the cloth to minimize flexing.  Switching to
the conventional design (see Gary Rasmussen's 080305 MMD posting) is a
good idea, but I would go one step farther and replace the slotted
pieces with the finest cabinet-grade plywood.  The result should be
just about as quiet, while eliminating any need for the bellows forms.

The original belts were made of leather with heavy thread to reinforce.
Replacement belts of cloth-impregnated rubber have been hard to find
through local industrial supply channels for over thirty years.  But
there may be suitable automotive belts more readily available.  The
modern belts are less prone to slippage than the old leather ones, so
with everything working at peak efficiency, I think I would want to add
an Ampico-type spill valve, set at just above maximum theme intensity
(reading taken with crash valve, if there is one, disengaged).

The commonest cause of a steamboat pump knocking is a bellows that
doesn't close completely because of either stiff original cloth or a
poor recovering job.  But the symptoms Daniel describes sound more like
a worn-out camshaft bearing.  I've never encountered this problem, and
guess it would be caused by lots of use, together with lack of lubri-
cation.  The lubrication system is designed to use grease, not oil.
Often the channel from the grease reservoir to the bearing surface is
clogged with dried-out grease, preventing any new lubricant from
getting through.  A thorough cleaning out of all three grease
reservoirs and associated channels should be a routine part of
rebuilding, but is often neglected, especially when the original
bellows cloth is not replaced.

Once the lubrication system is fully functional and the reservoirs
packed with a good general purpose automotive grease, the pumping
pistons should be twisted inward until a resistance is felt.  Then, as
the pump is running and the grease starts to distribute itself, the
resistance will go away and the pistons can be easily turned again
until again there is resistance.  Continue this easy twisting every
minute or so, never forcing beyond the point of resistance, until you
see new grease oozing out of the bearings.  Once the bearings have
proper lubrication, you could try tightening the two screws at the very
bottom of the casting holding the questionable bearing in place.  This
can take up some of the slack in a worn bearing; but if wear is severe,
the bronze bearing will have to be replaced.  This should be an off-
the-shelf item from an industrial supplier or bearing specialist; but
it will probably have to be slotted by a skilled machinist to match the
original.

Other problems to look for include the unlikely possibility that one of
the cams is loose on the shaft.  These are pinned to the shaft, with
the outer end of the pin ground flush with the cam surface.  I suppose
that solder could be melted into a loose joint to take care of this.
The large wooden tension roller for the four belts and the six
individual leather-covered rollers for each of the bellows also need
proper lubrication.  I'm guessing that graphite was used originally,
but many are found to have been oiled over the years.  If oil-free,
they should be kept that way; otherwise, more oil can be added.  Use
nothing lighter than SAE 90 weight.  And the rollers will all have to
be removed for adequate lubrication, without the excess running down
the sides of the roller while never reaching where it is needed.

Jeffrey Wood