I have in my shop a stack from a 1983 Aeolian Pianola which, as
suspected, has leaky valves.  The valve blocks are clear plastic.
The blocks appear to come off of the decks easily and can be broken
apart without damage.  Leather pouch and bleed appear okay.  The foam
valve is pierced with what looks like a nail which comes up through
a hole in the clear plastic stem, through the foam, through a metal
washer, and is crimped (crushed) at the top to retain the washer.

What is interesting is that even within this stack, there appears to
be at least two different types of foam material that was used for the
valves.  Both types leak.

I found a nice summary of a rebuilding technique in MMD from D. L.
Bullock on 2000.01.19.  He refers to using "gum rubber" for replacement
valves.  What is this product and where can I find it?  Have other had
luck with this product or are there other options here?  Any assistance
would be appreciated.

Joel Cluskey - Cluskey's Piano Works
Pittsburgh, Pennsylvania