Rack and Pinion - Oh, What a Rack

One of the major drawbacks of early-model trucks with a straight-axle, leaf-spring front suspension is the steering. Early-model standard mechanical steering boxes use links and arms to ensure both wheels turn in the same direction and at the same time. If you can, ignore the excess quarter turn of play in the steering wheel, the endless rotational ratio of sometimes 22:1, and the amount of uncomfortable bumpsteer.

Manual recirculating ball-steering turning forces are transmitted through ball bearings from a worm gear on the steering shaft to a sector gear on the pitman shaft. Ball-nut assemblies are filled with ball bearings, which roll along grooves between the worm-gear teeth and the grooves inside the ball nut. When the steering wheel is turned, the worm gear on the end of the steering shaft rotates, and the movement of the recirculating balls causes the ball nut to move up and down along the worm. Movement of the ball nut is carried to the sector gear by teeth on the side of the ball nut. The sector gear then moves with the ball nut to rotate the pitman shaft to activate the steering linkage. The balls recirculate from one end of the ball nut to the other through ball return guides.

Due to standard steering designs, the geometry of the multiple links and pickup points tends to create bumpsteer. Bumpsteer occurs when the wheels steer themselves without input from the steering wheel. This undesirable steering action is developed when the front tires and suspension encounter drastic road surface changes, like potholes, causing an uneven toe change that occurs as a result of the steering linkage not being parallel with the road surface. This will cause the wheels to change toe unevenly as the suspension undergoes jounce and rebound. Also, the steering-box worm gear design develops a noticeable amount of dead play in the steering wheel rotation, prior to the left/right turning action of the front wheels.

No Limit Engineering has a cure for the problem with its rack-and-pinion steering assembly kit. This unique unit simply mounts to a custom mounting bracket bolted to the backside of the straight-axle beam. Special tie-rod end adapters allow you to thread the factory tie-rod ends onto the new rack-and-pinion tie rods. Eliminating the bulky factory steering box allows for increased engine-compartment room for exhaust, header, and power-steering pump clearance.