Some are easy, some are *******
Take the drums out of m/c. You may be lucky, and they will separate. You will the need to get whats left of the bearing out, A bearing puller comes in handy, IF you are able to get it in place, other wise drift it out, use a metal bar going around it tapping it out. Some will just more or less drop out, others, ****
After that, bit of grease, clean shafts, push new bearings in, done. put drums back in m/c
SD, January 2012
