It has been many years since I have worked on a model B Ampico, but
I am guessing the cause of the splitting of the pump connectors would
be excessive pump pressure.

The reason for excessive pump pressure would be leakage in the leather
sleeve pneumatic, which holds the spill valve open.  If the leather
sleeve pneumatic is of poor quality and not completely sealed and air
tight, it can leak enough to allow the pump pressure to become so
intense it would either stall the motor or fracture the pump arms.

Without the motor running, test the tightness of the sleeve pneumatic
by sucking air through the tube that connects to it.  If you can sense
air coming through, then this may be the problem.

As for knocking, it is important that the pump arms be re-bushed with
good quality bushing cloth.  This can be a bit tricky, because over the
years the original bushing cloth has compacted and may contain tallow,
which would allow grease to be absorbed into the wood on bushing glue
surface, which in turn will not allow hot glue to adhere to the wood
when the pump arm is re-bushed.

To solve this, after the old bushing cloth is removed, soak the wooden
pump arms in lacquer thinner for a couple of days, to extract any
grease that might have migrated into the wood.  Then glue in the new
bushings.

The automatic adjusters, should be snug, and have a small amount of
tension on them from the spring.  Adjusting the spring tension too
tightly on the automatic adjusters might cause premature wear on the
felt bushings.

Bruce Clark