I think sustain pedals are causing Jacks to stick
Janssen upright; Pratt, Read & Co action.
Not a piano player, not a tech, but dead keys at the bass and treble extremes drove me to open it up and investigate. There were a number of keys where I think the action just needed to be exercised/cycled a few times and they loosened up, but I also found there were 7 keys on the bass end and 2 more in the treble where the jacks were trapped behind their felt stops so they would not release the hammer butts (4th photo). I was able to release the jacks after I discovered that the sustain pedals were prying up the hammer flange rail, lifting the hammer butts and their stops enough to let the jacks fall behind them. When I engaged the sustain pedal lever by hand, it lifted the butts/stops again and I could then push down on the jack tails to free them.
You can see in the pictures there’s a wooden rail (marked 1770) to which the hammer flanges and damper flanges are attached. The pedal lever wants to pry it up from the wooden rail (marked 655) directly below it. Should those rails be fastened/glued together so this cannot happen? Or is it perhaps that the sustain lever mechanism is too stiff? For now, I have simply left the sustain pedal and bass sustain pedal detached so they cannot lift that 1770 rail.
For background, this piano has been in my family since the early 80s, but rarely played until my kids took up lessons. There is a service sticker under the lid dated from 1981, and it’s possible that’s the last time it was serviced/tuned. The terms I used to formulate my question I learned from AI, so forgive me if they’re not the correct part names.
Thanks for any help.