Bleeding the brake hydraulic system (BMW 5 Series E12)

Remove the power steering reservoir cap and fill it with oil up to the normal level mark.

Start the engine and add oil to the reservoir as the level drops until it reaches the mark.

Quickly turn the steering wheel from one extreme position to the other until the air bubbles in the reservoir stop escaping.

If necessary, add oil to the reservoir, make sure the level does not drop, and replace the reservoir cap.