I have an ancient Kimball upright (manufactured est. 1905) and its sustain bar isn't lifting the lowest octave (approximately). When I take the action off and look a bit closer I can see that the sustain bar appears to be sitting further back in the areas affected. I take this to indicate that the sustain bar itself somehow has been misshapen?
The felt on the part of the damper levers that sit against the sustain bar in the areas of question shows zero signs of indentation, which to me suggests that this particular action has never actually worked correctly with the sustain bar.
So what can be done? I've discussed this with a technician casually as he was tuning the piano, and while he didn't look as closely as I just have, he said that due to the age of the piano it's likely something that cannot be fixed, either because attempt to re-bend the sustain bar could result in breakage due to age, and that a replacement part doesn't exist due to the age of the piano.
Do you guys concur with this?
I was thinking perhaps of augmenting the sustain bar in the areas affected with some medium that "extends" the sustain bar by the appropriate amount (~1/8 to 3/16 of an inch). Tape or some kind of tapered stick...
It seems really odd to me that the sustain bar would be bent this way on the section of the bar that is closest to the point of contact with the rod... i.e. it's bent in the opposite way you would think from years of use. If anything I would suspect that the higher octaves would be the first to be effected by a worn out sustain bar given the increased tension load.
The picture below shows when the dampers look like when I lift the sustain bar (sorry it's upside down)