1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 149Get this manual
REAR WHEELDRIVE MECHANISM Removethe snap ring, outer lock nut, lock nut thread and inner lock nut from the axle
Remove the brake disc with the hub from the axle
Remove the O-ring from the groove in the disc hubRemove the four socket bolts and the brake disc from the disc hub