chock your front wheels, release handbrake, jack rear of car up onto axle stands, remove rear wheels.if you have a cap covering wheel nut, remove it, using a hammer and chisel,tap up the stalking on the retaining nut, using a long bar with socket attached (could be 32mm but check) remove rear hub nut, and remove thrustwasher. you shoul now be able to take drum off, you might need to tap it with a rubber hammer to remove it if tight. you will need to renew hub nut, cap & seal.if you are a bit unsure, get a copy of the haynes manual for your car, (halfords, motor factors, or even a car boot sale if lucky) this will guide you though whole job in detail.
hope it helps
August 2010