Going fast is thrilling, and so is building the meanest, loudest engine your car can handle. However, none of that means much unless you can control that power. Steering is one type of control that is often taken for granted, but is essential. How your car steers, how many revolutions of the steering wheel it takes to complete a turn, and how the steering feels, is all very much important. Simply put, without the steering rack it would be impossible to change the direction of your vehicle, and that would be….well bad.
Article updates on 08/05/21. Original publishing date 08/18/16
What is a Steering Rack?
The steering rack is one of the most important parts of the steering system and. It transfers the movement from the steering shaft to the tie-rod shaft using a mechanical, hydraulic, or electric system. It is the main component that transfers the directional command from the steering wheel to the wheels.
At its very core a steering rack works by converting the rotational (circular) motion from the steering shaft to linear (straight) motion. Thanks to the gear ratio, it multiplies the turning force applied to the steering wheel and transmits it to the wheels. The servo systems in the rack also provide for smooth and easy steering wheel rotation.
Types of Steering Racks
Steering racks are generally divided into three main groups – Mechanical, Hydraulic or Electric. While all are still in use, the way they are presented above matches the technological progression of this steering device in modern cars. We started with mechanical ones, and now most cars use electric racks.
Mechanical Steering rack
Although there are many types of mechanical steering racks, the rack and pinion is the most common type of steering rack used in all passenger cars and light commercial vehicles. Hydraulic or electric systems can be added to this kind of rack.
In these systems, the circular motion of your steering wheel is transmitted to the pinion gear by the steering shaft. As the pinion gear rotates, it moves the rack shaft to the right or left, depending on the direction of rotation, with the help of the rack gears. This movement in the rack shaft reaches down to the wheels with the rods and tie rod ends.
Hydraulic Steering Rack
To increase driving comfort, wide-base and low-pressure tires are used in modern cars, and as a result, more steering effort is required due to tire friction. Steering torque can be reduced by increasing the gear ratio of the steering gear. Easy turning can also be achieved by using a wide steering wheel to provide greater turning force. However, even with these changes, it is still difficult to turn the steering wheel at low speeds. As a result, maneuvering a heavy vehicle in cities and tight spaces becomes a nuisance.
Various systems have been developed to reduce the steering effort and to enable you to steer the vehicle easily. To reduce the steering resistance, it is necessary to increase the torque generated in the steering rack. Usually, hydraulic pressure is used for this purpose.
There are two different types of hydraulic steering systems that assist the turning force. In one, the engine power is used to move the hydraulic pump. In the second version, an independent electric motor is used to drive the pump. Both generate hydraulic pressure.
Hydraulic pressure helps the pinion gear to move the rack. Pressure is applied to the rack depending on the amount of resistance that is being applied to the rack. Therefore, the pressure is increased when more steering force is required. The change in hydraulic pressure is provided by a control valve connected to the steering shaft.
Electric Steering Rack
The electrically assisted steering system supports the steering wheel via an electric motor. This motor drives a worm gear when it gets input from the steering wheel. The circular motion in the steering wheel is transmitted to the worm gear by the steering shaft.
There are multiple ball bearings between the worm screw threads and the worm screw nut threads. They circulate continuously within the ball nut and channels. The ball nut moves up and down depending on the rotation direction of the worm screw and turns the shaft left or right. This movement in the shaft reaches down to the wheels by going through command arms and tie rods.
In these systems, the friction is minimal, so it is easy to turn the steering wheel. It is preferred usually in heavy vehicles (trucks, buses) and premium cars. The impact from the road on your steering wheel (steering kickback) will be very mild with this system.
Main Components of a Steering Rack
Several components are used to build a steering rack. Let’s take a look at these components and their use within the system.
The task of the gearbox is to convert the circular steering wheel movement to linear (push-pull) movement while reducing the steering rotation force.
The rack and swivel-ball are screwed into the column or shaft of the steering wheel. It allows the distance between the joints to be adjusted according to the steering wheel position.
Tie Rod End
The tie rod ends are connected to the ends of the rods, connecting the gooseneck, the long intermediate rod, and the short rods.
Short Tie Rod
It connects the command arm to the gooseneck. It works like a link that transfers the left and right movement of the command arm back and forth.
What Are the Symptoms of a Bad Steering Rack?
The steering system, which is one of the most important control mechanisms of your vehicle, is a large system with many components. The hardest working part of the steering system and therefore the most malfunctioning part is the steering rack.
Of course, there will be some indications of malfunctions that may occur in the steering box. Let’s examine these malfunction symptoms together.
Today’s steering systems are usually supported by either a hydraulic or an electric power steering unit. With the help of hydraulic pressure, the system moves faster and becomes softer. When there is a loss in the hydraulic pressure, the rack and pinion will be exposed to more heat. In this case, the steering will become stiff. When this happens to you, you should check the steering hydraulic fluid first.
Hydraulic Foaming and Hydraulic Leakage
Loss of hydraulics is caused by mechanical problems such as loose connections, worn gaskets, etc. Necessary checks for this malfunction should be done without delay. In case of a leakage, the gears in the steering box will overheat. It’s easy to spot a power steering leak. It has a reddish color and will drip from the back of the engine to the ground from the driver’s side. In case of a leak, you’ll want to identify the source of the leak and fix it as soon as possible.
The condition of the hydraulic liquid in the system helps to give an idea about many issues. If the color of the liquid changes, the liquid foams, or its consistency changes, the hydraulic liquid must be replaced. Also, if the oil has a milky consistency, water may have entered your steering system.
Noises When Steering
The biggest causes of steering failures are usually lack of maintenance and lack of lubrication. If there isn’t enough lubrication, the metal parts will have to work by rubbing against each other, and they will overheat. In such cases, a high-decibel friction noise will occur during turning movements.
Vehicle Pulling to a Side While Going Straight
Wear on the steering rack can cause the vehicle to pull in any direction on the road while you are going straight. This problem arises especially if the connecting rods in the steering box are worn. When you encounter this problem, changing the steering rack will be the most logical solution.
Excessive Play in the Steering Wheel
Excessive play in the steering wheel is an indication of a malfunction of the gears inside the steering rack. You will need to steer more than usual when maneuvering to turn to the vehicle. In addition, forward or backward movements can be seen in the steering wheel while driving.
Observing the front wheels should give you an idea of the size of the gap. If the wheels react slowly during steering, there is a problem with the steering rack. The acceptable clearance on the steering wheel should not exceed 2.5 cm. Abrasions in the steering rack, joint problems, tie rod end gaps are the main causes of steering clearance problems. In the event of a malfunction, these three causes must be checked separately.
How Much Does it Cost to Replace a Steering Rack?
Steering rack prices will vary depending on the make and model of your vehicle and the steering rack type you want to use. If your steering rack has problems, you should brace yourself as these things cost a pretty penny. Also, steering rack replacement requires a good knowledge of the mechanics and moderate labor, so your “guy” may charge you a lot.
That being said, rebuilding a rack is often a viable option. Rarely will you find yourself in a situation where your rack is so damaged that it can’t be repaired.
Sometimes, though, it’s best to get a new unit. After all, it is the most important part of your steering system and a faulty one, or one that is on the very edge of being rebuildable, could potentially put your safety at risk.
Finding the Right Steering Rack for Your Car
Steering racks are always under heavy use while you are driving your car, so it is always possible for them to fail from time to time. If that happens to you, don’t worry! We are here to help you get your car sorted out! Just choose your car’s make and model from the drop-down menu, and you’ll get a list of all the parts specific to your vehicle. Always remember to use original and OEM quality parts.