Jack it up, wheel off. I assume it has 3 bolts holding the axle hub on? loosen them a few turns. Put two 10 or so tonne bottle jacks behind the hub between the hub and frame (a solid part!) with the pump facing down. Pump them up and using a copper hammer strike the bolts. The hub should shock free. Remove bolts and hub. Drill two small holes in the seal and screw in self tapping screws, use pilers to prise the old seal out. Install new seal, hub, bolts wheel.
Its not a hard job, the worst part is getting the hub off the axle. The taper lock is really tight!
