Having twice replaced the brake shoes on my blue Toyota, Clyde, and the wheel cylinders once, I decided the time had come to look deeper for the cause of the contamination of the brake linings.
If you go to the effort of replacing the axle seals, you ought to replace the rear axle bearings, too, if they are of uncertain vintage. The usual cause of axle seal failure is axle bearing wear.
I ordered new bearings and seals, and kept driving. Three out of four wheels braking is better than none. Meatloaf would agree.