For the Rear Brakes.
If the Rear Brake Hoses have never been replace I would replace them also.

If you are going to rebuild your own Calipers I would hold off on the parts for them until you have them apart and see what condition they are in. Some Members have had Calipers that the Pistons were frozen in and they could not remove the Pistons.
It is also possible to have pitted Pistons and ever badly pitted Caliper Bores. Depending on the condition of your original Calipers you might decide you want rebuilt ones.

When you do the Axles besure to keep the original Spacers that are on the Differential end of the Axle. They may stay in the Differential when you pull the Axles or the may stick and come out with the axle.

Also this just may have been a problem with myself but when I ordered the Differential Seals I ended up with 2 Pinion Shaft Seals and had to reuse the old ones. I would not pull the Old ones out until you have the new ones in your hands and know they are the correct ones.
I was lucky as the Old Seals have not leaked in the two years since the Axle exchange.

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84 300D, 82 Volvo 244Gl Diesel