Rack and pinion steering runs on the gear-established to convert the circular movement of the tyre into the linear motion necessary to turn the wheels. It also provides a gear reduction, therefore turning the tires is easier.
It works by enclosing the rack and pinion gear-established in a steel tube, with each end of the rack sticking out from the tube and connected to an axial rod. The pinion equipment is mounted on the steering shaft to ensure that when the steering wheel is turned, the apparatus spins, moving the rack. The axial rod at each end of the rack connects to the tie rod end, which is mounted on the spindle.
Most cars need 3 to 4 complete turns of the tyre to proceed from lock to lock (from far to far left). The steering ratio demonstrates how far to carefully turn the tyre for the wheels to turn a certain quantity. An increased ratio means you have to turn the steering wheel more to turn the wheels a particular quantity and lower ratios give the steering a quicker response.
Some cars use variable ratio steering. This rack and pinion steering system uses a different number of the teeth per cm (tooth pitch) at the heart than at the ends. The result is the steering is usually 
more sensitive when it’s turned towards lock than when it is near to its central position, making the car 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 rack and pinion china center of the steering rack.
As steering is vital for controlling your vehicle, it’s vital that you diagnose and restoration 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 convert the tyre, this turns a steering column, which rotates the attached steering shaft and a worm gear known as the pinion. This gear sits on the ‘rack’, a length of metal with a series of teeth cut into it. So as the pinion rotates, the rack moves either left or correct, depending on your steering input.
Power steering provides a device to 1 side of the rack with a hydraulically actuated piston inside. A rotary valve directs hydraulic fluid to either the proper or left side of the piston – based on the steering direction – which applies strain on the piston and reducing your time and effort needed to move the rack.
The rack-and-pinion gearset does a couple of things:
It converts the rotational motion of the steering wheel in to the linear motion had a need to turn the wheels.
It offers a gear reduction, which makes it easier to turn the wheels.
On most cars, it takes three to four complete revolutions of the tyre to help make the wheels turn from lock to lock (from far remaining to far right).