Here are some pics of a Caterpillar 18M Grader Circle Drive Motor that we picked up for repair & rebuilding. The pinion gear was broken in multiple pieces and the main shaft was damaged with all the drive splines having been sheared off. We did a complete rebuild to it with all new internal parts replaced as necessary. We set these up with a shim stack so they run extremely loose, or so the moldbaord will ratchet out or give away relatively easily. Adjusting the break away, or give, of the moldboard by adjusting the shim stack is extremely important for proper setup & longevity of the pinion gear, main shaft & the circle drive motor a as whole. This has to be done after the drive motor is mounted to the machine & hooked up to the blade (moldboard) for proper adjustment.
Motor Mission Machine & Radiator 5435 Desert Point Dr. Las Vegas, Nv. 89118 Ph: (702) 649-2366 or (702) 649-0648 Fax: (702) 649-4133 www.MotorMission.com Facebook.com/MotorMission