Rack and pinion steering uses a gear-arranged to convert the circular movement of the steering wheel in to the linear motion necessary to turn the tires. It also offers a gear reduction, therefore turning the tires is easier.
It works by enclosing the rack and pinion gear-arranged in a metal tube, with each end of the rack sticking out from the tube and linked to an axial rod. The pinion equipment 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 three to four complete turns of the steering wheel to move from lock to lock (from far right to far remaining). The steering ratio demonstrates how far to turn the tyre for the wheels to carefully turn a certain quantity. An increased ratio means you should turn the tyre more to carefully turn the wheels a specific amount and lower ratios supply the steering a quicker response.
Some cars use variable ratio steering. This rack and pinion steering system uses a different number of tooth per cm (tooth pitch) at the heart than at the ends. The effect is the steering is usually more sensitive when it is turned towards lock than when it’s 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 finish of the steering rack via the inner axial rods.
Centre remove – bolts attach the tie rods to the centre of the steering rack.
As steering is essential for controlling your vehicle, it’s vital that you diagnose and restoration any steering issues as fast as possible.
The chances are your vehicle has rack and pinion steering.
Thankfully, the fundamentals aren’t hard to grasp at all: it’s about turning rotational motion into linear. When you switch the tyre, this turns a steering column, which rotates the attached steering shaft and a worm equipment known 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 moves either left or correct, depending 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 fluid to either the right or left side of the piston – based on the steering path – which applies pressure on the piston and reducing the effort had a need to move the rack.
The rack-and-pinion gearset does a couple of things:
It converts the rotational movement of the steering wheel into 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 3 to 4 complete revolutions of the tyre to make the wheels turn from lock to lock (from far still left to far right).