Bass Bridge in old Ebersole Upright

[Dave Smith]

I am looking for advice on a Ebersole upright circa 1908 on which I am
practising tuning, repair and regulation.  The entire bass of the piano is
very dull -THUNK.  The bridge has no noticeable cracks, but does have two
interesting "features".  One is a buggered-up bolt which goes into the
bridge from its top at the extreme bass end.  This one is obviously a 'fix'
which didnt fix.  The second is a flathead screw countersunk very neatly
into the bridge at about its center.  Having not seen a lot of pianos yet, I
suspect this is also part of an attempted fix, but wonder if any of you have
seen older pianos with any screws like this through the bridge into the
apron??

It looks to me like someone tried to fix either the dead bass or maybe a
tuning instability with these pieces of hardware.  Before I attempt to
follow the procedure to loosen bass strings, remove bridge and apron, clean
up, reglue, etc, I did show it to Phil Bondi.  He advised me to also ask
here.
Help?

Dave Smith
Pine Island FL