There are basically two styles of vehicle steering systems, rack and pinion and worm gear box. Rack and pinion steering is one of the oldest types of steering systems and is still used today. Inside the rack body a flat rack gear moves in a linear direction driven by a circular gear called a pinion. The steering wheel is connected to the pinion gear (shaft).

Rack and Pinion Steering
Rack and Pinion Steering

The rack gear is connected to an inner tie rod end that is covered by a rubber bellow. The inner tie rod end is connected to the outer tie rod end. These rod ends have the ability to move in any linear direction. Finally, the tie rod end is connected to the wheel spindle.

Rack Bellow, Inner Tie Rod, Outer Tie Rod End
Rack Bellow, Inner Tie Rod, Outer Tie Rod End

Tie Rod End
Tie Rod End

A worm gear box style of steering system is constructed of two main parts much like the rack and pinion style system. The main part is called a worm gear; the other is a selector shaft gear. The worm gear is connected to the pitman arm and then to a center link and tie rod ends. The opposing end of the center link is supported by an idler arm, which is located on the opposite side of the frame from the steering box.

Steering Box
Steering Box (worm)

Steering can be either power or manual. Power steering utilizes a hydraulic pump mounted on the engine, and driven with a serpentine belt. The fluid in the system is held under pressure until the wheel is turned which releases the pressure and applies it to the steering system. The power steering system fluid should be checked at every service interval. Fluid leaks are a common problem on power steering systems. When a leak is detected inspect the system to determine the course of action, then remove damaged or worn parts and reassemble. Refill system with approved fluid for your particular vehicle. When the power steering system fluid is low a groaning noise will be heard when the vehicle steering is activated. This is caused by the power steering pump scavenging for fluid and taking in air.

When the engine is off or the system has run completely out of fluid it will be very difficult to steer the vehicle. It is advised not to move a vehicle with power steering when either of these conditions exists. Any steering component malfunction can cause the vehicle to be uncontrollable. All steering components should be inspected for "play" at regular intervals and replaced as needed. When steering components are replaced an alignment is required. Power steering system maintenance is required periodically according to the manufacturer's instructions for your vehicle. Most manufacturers recommend having the hydraulic fluid in the power steering system changed every 60,000 miles.

The opposing end of the center link is supported by an idler arm, which is located on the opposite side of the frame from the steering box. While some road noise is acceptable when driving, a clicking sound is an indication of a component that has failed or has come loose. Many suspension components are in action while the car is driving include shocks, struts, ball joints, lower control arm, bushings, sway bar links and more.


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-30)