Laelia had an ancient autopilot when I bought her - a Cetec Benmar. The drive motor works but not the rest of the electronics. I have removed all of the components because I will be installing Monitor windvane instead. The quadrant bolts onto the 1 1/2" rudder post. It is 9 1/2" from the center of the bore to the outer edge of the quadrant. I looked at the Edson site and it looks to me like the quadrant alone sells for about $450. I am selling the quadrant/rack and the pinion combo for $250 plus shipping.
(http://i1151.photobucket.com/albums/o638/SailorRalph/_MG_7437.jpg)