The brake assembly can be tricky. The inside metal brake disc slides onto the keyed shaft, followed by one friction disc, the spring, and hub. The 21 ball bearings need to be installed around the hub, inside the ratchet. We tapped the shaft keys for the outer brake disc onto the shaft and used their tension to compress the spring, pushing the hub downward. The lightly greased balls can then be dropped in place. With the second friction disc dropped onto the ratchet and the outer brake disc slid onto the shaft, the assembly can be secured with a new snap-ring.