hammer butt springs

[Bob Simmons]

I've got a Yamaha console (about 13 yrs. old) that has suddenly
developed a problem with the loops, which hold the hammer return springs,
starting to break. (Schwander style, you know). Why would these be
breaking? I'm wondering if the material of the loops is not treated with
moth repellant, and if so may have been weakened by little critters? Would
some type of corrosion on the springs have begun to act as an abrasive?

By the way, what material should I replace these with? I've used dental
floss for repairs, but I'm sure that's not the appropriate material
(actually I'm not sure, but I'm guessing). But first I want to have at
least a theory of what has caused the problem so it doesn't come back as
soon as I'm done.

Bob Simmons, RPT
CSU San Bernardino