Powersteering -what is it?

Every modern car has some form of powersteering unit.  A system designed to make turning the steering wheel & wheels of a car with ease.Without it and most drivers would need to go to the gym regularly to be able to park their car. Through a system of pumps and pistons , pressurised oil is used to assist the mechanical steering within the rack. Many modern cars use both mechanical and computerised systems to achieve effortless control of a car and still maintain a sense of 'feel' when driving.

What is a rack, pump or box?

A 'rack' is the piston if you like, that has oil pumped through it that pushes  rack ends that are attached to the wheel hubs (your wheels are bolted to the hubs) These racks control the direction the wheels face.

A pump is the 'heart' that physically pushes the oil through the rack to create movement. A Box is used in place of a rack sometimes The steering wheel determines where the oil is directed to creat a change in direction.