It's not all that hard to change the axle seals.
1- Remove the rear wheels
2- Remove the brake drums
3- Remove the brake line from the back of the wheel cylinder
4- Remove the parking brake cable from the back of the backing plate
5- Remove the 4 nuts that hold the axle to the housing (on the backing plate area)
6- Remove the axle assembly
7- Remove the seal, and install a new seal
8- Reinstall the axle, and bleed the rear brakes
9- Replace the rear brake shoes
Good Luck!!