Clicking key only when action in piano

Question

I recently took out the action on my grand piano to fix some clicking noises. There were two issues I fixed:

1. I noticed the screws behind the wippen were extremely loose and a loud clicking noise would occur if I tapped on the back of the key. I tightened the screws and the clicking noise stopped.

2. The hammer heads were loose, so I used a very small amount of glue so the hammer heads wouldn't move around so much. I stuck out my hand and hit it with the hammer a bunch of times to see if a clicking noise would occur, but one didn't.

After doing this I put the action back in the piano; however, a clicking noise still occurs on some of these notes! I thought maybe it's because the screws had immediately loosened, but they haven't. Additionally the clicking noise doesn't occur after I take the action out of the piano again.

What could be wrong?

Answer 1

This is caused by a lack of felt where the back of the key meets with the damper lever. The damper lever is striking the wood on the back of the key causing a clicking noise:

The obvious fix is to glue down new felt and make sure it covers the area of the back of the key that comes in contact with the damper lever.