Rack and pinion steering runs on the gear-arranged to convert the circular movement of the tyre into the linear motion necessary to turn the tires. It also offers a gear reduction, therefore turning the wheels is easier.
It works by enclosing the rack and pinion gear-arranged in a steel tube, with each end of the rack sticking out from the tube and connected 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 connects to the tie rod end, which is attached to the spindle.
Most cars need 3 to 4 complete turns of the tyre to go 
from lock to lock (from far to far still left). The steering ratio shows you how far to turn the steering wheel for the wheels to carefully turn a certain amount. A higher ratio means you need to turn the steering wheel more to turn the wheels a specific amount and lower ratios supply the steering a quicker response.
Some cars use adjustable 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 effect is the steering can be more sensitive when it’s switched towards lock than when it’s close to its central placement, 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 finish of the steering rack via the inner axial rods.
Centre remove – bolts attach the tie rods to the center of the steering rack.
As steering is vital for controlling your car, it’s important to diagnose and repair any steering problems 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 about turning rotational motion into linear. When you convert the steering wheel, this turns a steering rack and pinion china 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 some teeth cut into it. So as the pinion rotates, the rack movements either left or right, based on your steering input.
Power steering adds a device to 1 side of the rack with a hydraulically actuated piston inside. A rotary valve directs hydraulic liquid to either the proper or left aspect of the piston – depending on the steering path – which applies pressure on the piston and reducing your time and 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 needed to turn the wheels.
It provides a gear reduction, making it simpler to turn the wheels.
On most cars, it takes three to four complete revolutions of the tyre to make the wheels turn from lock to lock (from far left to far right).