The brakes on all three models of Diablo are identical. A simple caliper pressing two brake shoes against a rotor which is splined to the input shaft of the gearbox.
The brake rotor is softer than the shaft making the rotor the sacrificial lamb if you will. Often if the rotor fails over time, the splines on the shaft are fine and thus just requires a new brake rotor. The splines are unique. Having a spare rotor on hand is a good idea.
Maintenance on this unit is straight forward. Pull it apart and keep it clean. Lubricate the “through the gearbox” bolts so the caliper can slide and maintain a centered position over the rotor. Lubricate the two round push pins. Be sure to reinstall them with the rounded ends outward toward the brake arm lever. Between the brake shoe and the push pins should be a steel disc. Keep the rotor polished clean.
Brake shoes used in this caliper are round. The back caliper shoe is glued in place. Again, having a spare set of shoes on hand is a good idea.
For adjustment, locate the arm straight up and slightly left of noon by adjusting the cable stop. Then remove the cotter pin and adjust the castle nut inward until a slight drag can be felt when spinning the rotor. Reinstall the cotter pin.