I checked out my flex last night, and before doing anything I tried moving or jiggling the backing plate with my hand. It appeared to be a tad bit loose, so I reached for my allen keys. I then held the button on top of the head to lock the gears, I tightened the bolt on the backing plate, it was pretty tight already, and only moved very little about a quarter turn if that. I hope this did the trick, I'll post after my next use.