The brush bar on the vacuum can wear with use. If your brush is scratching your floor, or not cleaning as well as it used to, then you may want to replace your brush bar.
Lay the vacuum on its top so that the brush bar faces you.
Using a quarter, turn the three soleplate fasteners 90 degrees to the left.
Holding the soleplate on both sides, tilt it down and away from the vacuum.
Remove the soleplate from the vacuum.
Turn down the squared tabs on the brushbar so that they face outward.
Use a screwdriver to pry the belt up from the brushbar.
While holding the belt, pull the brushbar to the left and remove it from the vacuum.