Hi Lynn, The bearings are easily replaceable on the WD12 but there are two different versions of drum spider using different sized bearings and shaft seal. To find out the correct parts you need to measure the shaft size at the rear bearing - it will be either 22mm or 26mm (most common).
For 26mm - parts required are
Front bearing size = 6206 2Z
Rear bearing size = 6205 2Z
Shaft seal = C00082696 standard oil seal.
For 22mm - parts are:
For 26mm - parts required are
Front bearing size = 62052Z
Rear bearing size = 62042Z
Shaft seal = C00096186 oil seal.
Hope this helps.
martin114
February 2005