The rack and pinion steering linkage is comprised of seven basic parts depending on how you count the components. They are the steering wheel, steering shaft, pinion, rack, tie rod, control arm and wheel. These parts form a mechanical extension from your arm input to the wheel. When you turn to the right, each step of this mechanical system reacts in kind until the front wheels turn the direction you wish to go. Let’s take a closer look.
We’ll start at the top – the steering wheel. When you turn the steering wheel, you are really turning the shaft. The steering shaft runs into the engine compartment. At this point, it connects to the pinion. The pinion is a metal bar with a gear on the end of it. The pinion slots into the rack. The rack runs horizontal between the tires and has grooves matching those on the pinion gear. When the steering wheel is turned by you, the shaft turns and the pinion does as well. As the pinion gear moves, it pushes or pulls the rack to the left or right and that turns the tires in or out.
The rack does not connect directly to the wheels. Instead, it connects to tie rods. Tie rods are adjustable mechanism that can be lengthened and shortened slightly. This is important as this adjustment is a critical part of the alignment process for a car. Tie rods also serve as a stress break point for the system, creating a hardy buffer between the rack and any damage that might occur to the wheel area.
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