[pianotech] singing sustain, what to do?

[Mike Spalding]

Relatively new small Essex grand.  When the sustain pedal is operated 
very slowly, it makes a moaning noise.  Removed the action, removed the 
pitman, and raised the tray by hand, heard the noise.  Here's what I 
think is causing it:  the lift tray is aluminum, the felt is soft and 
thick, and the tray pivot is nowhere near the underlever centers.  So 
when the tray is lifted, the underlevers slide on the felt, playing the 
aluminum tray like a violin.  What to do?  My inclination would be to 
replace the tray felt with something harder/smoother, and polish the 
undersides of all the underlevers with 400 grit sandpaper or finer.  But 
before going to all that trouble, I thought I would toss the question 
out to the list, and see if anyone else has encountered this, and what 
you did to fix it.  Any thoughts?

thanks

Mike Spalding