A rotary lever disc brake actuating mechanism and a method for operating the rotary lever disc brake mechanism is provided. The mechanism includes a rotary lever which rotates a pinion to further rotate brake pad application racks. The racks are arranged to rotate toward an inboard brake pad to advance the brake pad toward a brake disc. The racks may further cooperate with lateral pins fixed to an outboard portion of the brake such that the outboard portion simultaneously advances an outboard brake pad toward the brake disc when the racks rotate. The brake mechanism may be assembled into a cartridge to be placed within an inboard portion of a brake caliper. The brake caliper may be located on a caliper mount via adjustment pins, whereby during new brake pad installation the caliper is self-centered by application of the brake, followed by securing the caliper to the adjustment pins.