NTN-SNR is advising mechanics to always replace the retaining bolts when changing the engine damper.
During the original assembly or replacement of a damper, high tightening torques are applied to the retaining bolts. Some applications require secondary tightening angles to be applied once the torque settings have been reached.
Once the retaining bolts are tightened correctly they have reached their elastic limits. The bolts lengthen or deform according to the manufacturer’s specifications, once stretched and deformed the bolts cannot be used again. If a stretched or deformed bolt is refitted there is a high risk of it not tightening correctly or snapping.
Not replacing the used bolts means you run a high risk of an accessory system failure, in some cases this may result in serious engine damage.