Paradoxbox - if you are experiencing a 'centre-detent' feeling in your yaw pedals, it could be due to Brinelling.
When the tail rotor drive shaft - the bit actually attached to the TR and driven by the TR gearbox - rotates in its pitch change bearings in the same position (cruise flight at constant speed for example) the bearings can wear a groove in the drive shaft - the is Brinelling.
We sometimes saw this in the Wessex and it manifested itself in the 'centre-detent' feeling where more force was required to get the bearing to 'climb out' of the groove.