hammer them out, using a hammer and stout bar, lever out the rear seal, the inner bearing knocks out from the BACK, the rear one you knock out from INSIDE the drum. (do this one first as more material to hit due to shaft size being smaller) try not to damage the recess where the new bearing must sit.if you do damage the high spots MUST be removed.
On reassembly put a smear of oil around the outer edge of bearing to help it SLIP then gently tap the new bearing in to the recess by tapping opposite sides i e 12 & 6 position, 3 & 9 position this ensures bearing enters squarely, carry on tapping this way till the bearing is sitting down on the internal shoulder( you may need to swap to a large socket just smaller than the bearing or an old screwdriver towards the bottom) if using screwdriver tap on the outer race only, repeat for the opposite side bearing refit the seal to the rear .
wirecutterman
July 2009