Rack and pinion steering runs on the gear-established to convert the circular movement of the tyre in to the linear motion required to turn the tires. It also provides a gear reduction, so turning the wheels is easier.
It functions by enclosing the rack and pinion gear-set in a metal tube, with each end of the rack protruding from the tube and connected to an axial rod. The pinion gear is mounted on the steering shaft to ensure that when the tyre is turned, the gear spins, shifting 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 move from lock to lock (from far to far still left). The steering ratio shows you how far to carefully turn the tyre for the tires to turn a certain amount. An increased 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 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 effect is the steering is usually more sensitive when it’s switched towards lock than when it is near 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 end of the steering rack via the inner axial rods.
Centre take off – bolts attach the tie rods to the centre of the steering rack.
As steering is essential for controlling your vehicle, it’s important to diagnose and restoration any steering problems as fast as possible.
The chances are your car has rack and pinion steering.
Thankfully, the basics aren’t hard to grasp at all: it’s all 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 gear sits on the ‘rack’, a length of metal with some teeth cut into it. So as the pinion rotates, the rack techniques either left or correct, depending on your steering input.
Power steering adds a device to one aspect of the rack with a hydraulically actuated piston inside. A rotary valve directs hydraulic fluid 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 a couple of things:

It converts the rotational motion of the steering wheel into the linear motion had a need to turn the wheels.
It offers a gear reduction, which makes it simpler to turn the wheels.
On most 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).