how do i replace brushes in bosch wfo2466 w/machine?

i think bosch brushes on classix 1200 wfo 2466 need replaced again. were replaced before but person removed motor. do i have to do this or can they be changed with motor in place. used to do my hotpoint no problem. also machine starting to smell musty, was not taking fabric conditoner away, have tried to clean and run several 90degree washes recently. any help appreciated. thanks