Rack and pinion steering runs on the gear-established to convert the circular motion of the steering wheel into the linear motion necessary to turn the tires. It also provides a gear reduction, so turning the tires is easier.
It works by enclosing the rack and pinion gear-arranged in a metallic tube, with each end of the rack sticking out from the tube and linked to an axial rod. The pinion gear is attached to the steering shaft so that when the steering wheel is turned, the apparatus spins, shifting the rack. The axial rod at each end of the rack links to the tie rod end, which is mounted on the spindle.
Most cars need 3 to 4 complete turns of the tyre to go from lock to lock (from far right to far left). The steering ratio shows you how far to carefully turn the tyre for the tires to turn a certain amount. A higher ratio means you have to turn the steering wheel more to turn the wheels a particular amount and lower ratios supply the steering a quicker response.
Some cars use variable ratio steering. This rack and pinion steering program runs on the different number of teeth per cm (tooth pitch) in the centre than at the ends. The effect is the steering is more sensitive when it’s turned towards lock than when it’s near to its central position, making the automobile more maneuverable.
There are two main types of rack and pinion steering systems:
End take off – the tie rods are attached to the end of the steering rack via the inner axial rods.
Centre take off – bolts attach the tie rods to the center of the steering rack.
As steering is essential for controlling your car, it’s vital that you diagnose and repair any steering problems as quickly as possible.
The chances are your car has rack and pinion steering.
Thankfully, the basics aren’t hard to grasp at all: it’s about turning rotational motion into linear. When you turn the steering wheel, this turns a steering column, which rotates the attached steering shaft and a worm equipment referred to as the pinion. This gear sits on the ‘rack’, a length of metal with some teeth cut involved with it. In order the pinion rotates, the rack moves either left or right, depending on your steering input.
Power steering adds a device to one side of the rack with a hydraulically actuated piston inside. A rotary valve directs hydraulic fluid to either the right or left part of the piston – depending on the steering direction – which applies pressure on the piston and reducing the effort needed to move the rack.
The rack-and-pinion gearset does two things:

It converts the rotational movement of the steering wheel into the linear motion had a need to turn the wheels.
It provides a gear reduction, which makes it easier to turn the wheels.
On the majority of cars, it takes 3 to 4 complete revolutions of the tyre to help make the wheels turn from lock to lock (from far remaining to far right).