[ Warren Officer wrote in 160428 MMDigest:

> The complaint was the pump is making the piano shimmy.

Hi Warren,  I have a 1923 Chickering Centennial Ampico grand with
upside-down valves that is doing the same thing.  I rebuilt it over
30 years ago and it has always done it, except for a few months last
winter when it stopped shaking and was rock solid while running.

Now it's shaking again.  The keyboard end moves back and forth a good
half-inch.  At first I suspected that the belt or the cloth had taken
a set, but now I'm not sure if that's the cause.  Perhaps a valve in
one of the pumps is not sealing, but my piano plays strong as ever.

Please let us know what you find the problem to be.  I'd like for mine
not to shake too.

Mike Clemens