I have seen two 26-27 with cracks going from the rivets down the housing. Both cars have 21 inch wheels. How common is this and would removing the quadrant and welding be a good fix.
You find them sometimes in fractured shape, for me its easier to get another column, most times a used whole complete column with gear case and shaft and rods are about $30.
Welding if done with care and grinding out the inside bead if welding thru the crack, as the inside of the column needs to be smooth for a tight fit of the gear case lower section.
Welding it should be a good fix.