I have been working on a Waddington Welte Licensee for some months now.
The problem seems to lie with the valves, I think most likely the
secondary valves.  The collector I purchased it from had started to
restore the instrument and therefore I am not sure that the valves have
not been tampered with.  The piano was made in 1926 so I am sure that
the valves are probably porous.

With the pump running and the expression system giving the stack full
vacuum -- well, it either does not play at all or so lightly that the
hammers just move!

Any advice would be greatly received.  Could it be the pump?  The valve
facings?  Valve travel?

Secondly, what sort of leather would you recommend for the valve facing?
I understand that the travel of the secondary valves should be around
1/16-inch?

I have worked on many players but this machine is driving me mad.
These instruments have the Standard action that I understand is very
common in the US but very rare in the UK.

Where do you think I should go from here?

A very frustrated Jonathan Holmes