Rack and pinion steering uses a gear-arranged to convert the circular movement of the steering wheel in to the linear motion required to turn the tires. It also provides a gear reduction, therefore turning the wheels is easier.
It works by enclosing the rack and pinion gear-set in a steel tube, with each end of the rack sticking out from the tube and linked to an axial rod. The pinion gear is mounted on the steering shaft to ensure that when the tyre is turned, the apparatus spins, moving 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 proceed from lock to lock (from far right to far still left). The steering ratio demonstrates how far to turn the tyre for the tires to turn a certain quantity. An increased ratio means you have to turn the steering wheel more to turn the wheels a particular amount and lower ratios give the steering a quicker response.
Some cars use adjustable ratio steering. This rack and pinion steering program uses a different number of teeth per cm (tooth pitch) at the heart than at the ends. The result is the steering is definitely more sensitive when it is switched towards lock than when it is near to its central placement, making the automobile more maneuverable.
There are two main types of rack and pinion steering systems:
End take off – the tie rods are mounted on the finish 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 vital for controlling your vehicle, it’s vital that you diagnose and repair any steering issues as fast as possible.
The chances are your vehicle has rack and pinion steering.
Thankfully, the basics aren’t hard to understand at all: it’s all about turning rotational motion into linear. When you switch the steering wheel, this turns a steering column, which rotates the attached steering shaft and a worm equipment referred to as the pinion. This equipment sits on the ‘rack’, a length of metal with a series of teeth cut involved with it. In order the pinion rotates, the rack moves either left or correct, based 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 liquid to either the proper or left side of the piston – depending on the steering direction – which applies strain on the piston and reducing the effort had a need 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 needed to turn the wheels.
It offers a gear reduction, making it simpler to turn the wheels.
On the majority of 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).