Below is an exploded view of the differential of your SC directly from the Case/IH site. The only seals shown behind the brakes are in the differential bearing carrier. Through Case/IH, those seals are $27.14 ea. Through Saeli Implement they show a couple of prices. One is $12.70, and another I saw was $14 and change. They (Saeli) also carries the gasket and O-ring for the bearing carrier.
Discs unless worn out, can be cleaned up. An old Case collector showed me how to take a propane torch and "boil" the oil out of them. I chose to hang them on a piece of #9 wire, and held the torch a couple inches from the disc, and go in a circular motion on the surface of the disc. Oil will literally boil out of the disc surface. It takes a while, so be patient. I further cleaned with brake parts cleaner, then buffed with a roloc pad, on my air angle grinder. A medium gasket removing disc works great.
Pretty much the same brake setup on my old 310B I had. It is recommended in the repair manual, to only do one side at a time, or it will let the differential drop in the diff. case.
The 310B had large Phillips head, bevel headed screws to hold the bearing carrier in. I replaced them with a hex type, bevel screw, so as to make reinstallation a lot easier, since they need to be torqued. Even though as I recall it was only like 10-15 inch lbs. No cam out on the screw heads.
Hope this helps..!!
http://www.saeliimplement.com/index...category_id=30&option=com_virtuemart&Itemid=3