JACOX steering

This company was founded in 1906 in Saginaw, Michigan. Three men with last names: Jackson, Church and Wilcox created Jacox, a trade name created from all of their last names. Buick bought the Jacox facility in 1909.

After being separated from Buick in 1917, the company was established as the Jackson, Church and Wilcox Division, becoming GM’s first parts manufacturing division. The name was changed to Saginaw Product Company in 1919 and to Saginaw Steering Gear Division in 1928. The brand name of the products was changed from Jacox to Saginaw in 1930. In 1985, the divisions name was shortened to Saginaw Division.

During the early 1990s, the division was folded into GM’s Automotive Components Group, which in 1995 became Delphi Automotive Systems.  Saginaw Steering for 90 years was a part of GM.


Jacox boxes were used in many American makes and there are variations of internal components on boxes that look the same externally. The picture below shows 2 half nuts form 2 aparrently identical boxes. One is quite obviously shorter than the other.

The section on top of the nuts is located via dowels and is easily removed. This transfers the movement to the steering shaft and is prone to breaking. A good engineering shop can replicate and harden these items from a sample. They may be available as NOS items but the author has so far had no luck in this endeavour.

1911 Jacox advertisement

At right are the components that make up a typical Jacox steering box. The main steering shaft to the left of the half nuts can have either round rollers or square sections that the half nuts push against. The square ones can be rotated during servicing to provide a fresh working surface. Shafts may need to be built up by hard chrome or metal spray to correct tolerances and bushings are easily replaced.

One of the advantages inherent with this steering system is that there is no difference in parts for left or right hand drive. The change over is achieved by swapping the position of the left and right half nuts. You will soon realise you have it wrong when you turn left and go to the right & visa versa.

Adjustment consists of winding down the threaded collar where the collumn meets the box.