[Blackbirdws6]

If you are getting a vibration (resonance) in the system, changing its weight can change the frequency at which is will vibrate. Seems like they may have been getting close to a harmonic freq. (think of that bridge that went all wavy and fell apart) and this solved the problem.

Just hope the weights don't fall off and they recall these calipers for the owners that have this on their cars.