A parking brake mechanism in a caliper body has a piston assembly slidably supported within the caliper body. A first gear is rotatable in the caliper body about a first axis. A second gear is rotatable in the caliper body about a second axis. The first and second axes are generally perpendicular. A ball-ramp assembly is operably disposed between the second gear and the piston assembly. The ball-ramp assembly translates rotational displacement of the second gear into axial displacement of the piston assembly to actuate the parking brake mechanism.