Rack and pinion steering uses a gear-set to convert the circular movement of the tyre in to the linear motion necessary to turn the tires. It also provides a gear reduction, therefore 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 protruding from the tube and linked to an axial rod. The pinion equipment is mounted on the steering shaft so that when the tyre is turned, the gear 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 to far left). The steering ratio demonstrates how far to carefully turn the steering wheel for the wheels to turn a certain amount. A higher ratio means you should turn the steering wheel more to carefully turn the wheels a particular quantity and lower ratios supply the steering a quicker response.
Some cars use adjustable ratio steering. This rack and pinion steering program runs on the different number of the teeth per cm (tooth pitch) at the heart than at the ends. The result is the steering is more sensitive when it is turned towards lock than when it is close 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 attached to the end 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 essential for controlling your car, it’s important to diagnose and repair any steering problems as fast as possible.
The chances are your car 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 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 involved with it. In order the pinion rotates, the rack movements either left or right, based on your steering input.
Power steering adds a device to 1 part of the rack with a hydraulically actuated rack and pinion china piston inside. A rotary valve directs hydraulic fluid to either the right or left aspect of the piston – depending on the steering direction – which applies strain 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 tyre in to the linear motion needed to turn the wheels.
It offers a 
gear reduction, which makes it simpler to turn the wheels.
On many cars, it takes three to four complete revolutions of the steering wheel to help make the wheels turn from lock to lock (from far remaining to far right).