Hi Kerry, you're wrong ! The Coaxial power steering was used on '57 models (and perhaps before but itsn't the same housing) but the '58 used the Constant Control power steering (except some earlier '58 models which have the Coaxial). The Constant Control was used until 64 on some MoPar. The Coaxial has a very long housing which protudes below the dash. That explains why ther's a removable plate on the floor: you couldn't remove the steering assembly without removing the plate ! You "extract" the steering from inside the car. The plate remains on '58 but you could remove the Constant Control steering from under the car. The '58 Constant Control has a round "bell" cover at the top where you find the adjusting screw, the '57 Coaxial has a square cover for the adj. screw. -- Philippe COURANT (Pau, France) Imperial 57 Crown convertible Buick 58 Roadmaster sedan - American Car Club de France (ACCF) : http://www.accf.com - Chrysler Imperial France : http://www.ifrance.com/c-i-f - Cadillac " Standard of Excellence " : http://www.ifrance.com/accf-cad - SportsCars : http://www.ifrance.com/accf-sprtcar