After a year of using (or sitting), condensation leads to rust. Rust leads to scratches. And scratches lead to friction and eventual bearing failure. To pack the bearings, you just jack up the axle and safely support it. Remove the wheel and tire. Remove the dust cap. Remove the cotter pin. Back the retaining nut off and wiggle the hub assembly to loosen the outer bearing on the axle. Remove the retaining nut, washer, and outer bearing. Slide the hub assembly off the axle stub. Clean the brake shoes, backing plate, and axle stub so they are ready for reassembly. Knock the inner bearing and grease seal out of the hub. Clean the brake dust from the brake drum, and the grease and dirt from the hub. Clean ALL, I repeat, ALL the old grease out of the bearings.