NEW AUSCO HYDRAULIC BRAKE 94140 5318 7990 THE OUTSIDE DIAMETER IS 6-3/4 " THE INSIDE DIAMETER IS 4" THE DISTANCE FROM THE MIDDLE OF THE TOP BOLT HOLES IS 5-3/4" APART, THE SHAFT IS 1-1/4 LONG, SHAFT DIAMETER IS 9/16", THE HEIGHT OF THE UNIT IS 3" , THE DISTANCE FROM THE 4 BOTTOM BOLT HOLES IS 6-3/4" APART ON CENTER OF THE HOLE.