Brushes. I have changed on my Bosch, and Hoptoints previously.
Very easy once the motor is out.
On the Bosh it is at the bottom so inverting the machine and unbolting is easy. On the old Hotpoint it was on top so just had to take the lid off and unbolt the motor.
You will find that there is a simple plug to the motor then remove it then the 2 brushes are accessible and oly bclipped in. Easy Peasy!
Espares is an excellent scource of parts and much cheaper than appointed service outlets.