The Beckwith stack was probably the most aggravating leaker I ever
dealt with.  I found the problem was the large red fiber donuts
that are the inside seats.  They warp pretty badly and there was
no source for replacement at the time I needed them.  I have since
had thousands made and I now replace them.  The problem was solved
on the several Beckwiths I have restored since then.

Also another common problem with the valves is the inside valve must
rock slightly and must be airtight at the center hole which may be
solved by adding a pouch leather donut under the fiber side of the
valve.

Doug L. Bullock
Alton, Illinois
http://www.thepianoworld.com/