What is a steering box?
A steering box is one of the most important parts of a car and especially an important part of the car’s steering system. A steering box’s role is to help move the wheels in the same direction that the driver moves the steering wheel.
The car’s steering system is also responsible to transmit and to amplify the force and the direction applied to the steering wheel to the two wheels.
Between the steering wheel and the steering box, there is an axle that connects those two parts. So, when you turn the steering wheel to the right or left, this movement is transmitted by this axle to the steering box which, in turn, transmits the movement to the wheels in the wanted direction.
Types of steering boxes and racks
There are quite a few types of steering boxes or racks like mechanical, hydraulic, electric-hydraulic, electrically assisted, etc. The steering boxes are classified according to the type of the steering and driven element through which the momentum is transmitted from the steering wheel to the axis of the steering lever.
Some types of steering boxes and racks are more efficient and others are simpler. The simplest steering box is the one with no power steering that has only a toothed shaft and a crown.
Believe it or not, there are still cars that use this type of steering with no power steering, like in older models, you have to work a little bit hard when you turn the steering wheel, especially if the car is not moving. 🙂
Thus, the power steering or power assist is a great invention to help the driver get rid of that stiff steering wheel sensation.
Steering box vs steering rack
I guess you saw above that I am using the word “rack”. A steering rack is basically the new generation of steering boxes used today in cars with different types of power-assisted technology.
The steering box used to be on older car models that did not have a power-assisted help and it was later replaced by a steering rack.
Most steering boxes have a hydraulic power steering as assisted help. This is an older technology that was used 10-15 years ago. This system uses a pump to increase the pressure of the liquid.
Today’s cars are mostly equipped with a steering rack that uses an electric power steering system.
The hydraulic power steering
An older version of the assisted steering system is the hydraulic power steering that helped the steering box. It consists of a steering pump, links, bearings, bar ends, filters, wheel bearings, and other mounting elements.
The hydraulic power steering appeared in 1951 when Chrysler first invented hydraulically assisted steering. This type of steering was first called the “Hydraguide” and was first mounted on an Imperial Chrysler. The hydraulically assisted steering box has a fairly simple mode of operation.
The box has at the end of the column a small piece that connects two valves. In some cases, there is a sensor that senses the steering wheel movement, and the steering dictated by the driver opens a valve which in turn is connected to a servo hose that drives the oil under pressure in the steering box to help the wheels move.
Basically, using the oil pressure makes the driver’s job easier, you move the steering wheel slightly and the heavy job is done by the hydraulic system.
The electric power steering
The electric power steering is on most cars today. This system uses an electric motor to help the steering box. In this model, there is no axle between the steering wheel and the steering box.
The steering wheel is connected to a sensor that detects the movement, it further transmits the information to a motor on the steering box.
The advantage of this system is a sensor that detects the car’s speed and it moves the wheels faster or slower. Electric power steering no longer has all the elements mentioned in hydraulic power steering and this helps the car consumption by lowering it.
The difference between normal and electrically assisted power steering is that in electrically assisted power steering, the power steering pump is driven by an electric motor, not by the serpentine belt, so it no longer depends on the engine RPM.
The rack and pinion steering system
In nowadays, most cars are equipped with the rack and pinion steering system.
The rack and pinion steering mechanism is considered more modern and convenient. Unlike the previous unit, this device is applicable to vehicles with independent steering wheel suspension.
Assembled in one body, usually made of light alloy, it is attached directly to the car body. At the ends of the rack, there are threaded holes for fastening the steering rods.
The gear is mounted on the steering shaft and is in constant engagement with the rack. During the rotation of the steering wheel, the rack moves in the horizontal plane.
As a result, the steering rods connected to it also move and drive the steered wheels. The gear-rack mechanism is distinguished by its simplicity of design and high efficiency.
Its advantages also include:
- fewer hinges and rods;
- compactness and low price;
- reliability and simplicity of design.
On the other hand, this type of steering system is sensitive to shocks from road potholes or bumps. Any shock from the wheels will be transmitted to the steering wheel.
This video explains how the rack an pinion steering system works
Symptoms of a bad steering box or steering rack
Oil leaks from the power steering.
If you notice that the steering box is difficult to handle and you see leaks on the ground, that could come from the power steering.
In a hydraulic power steering, the power steering fluid is not allowed to leak unless there is a crack somewhere, maybe a worn gasket or mechanical problem.
To know that the leak comes from the power steering fluid and not from the other types of fluid is to check its color. The power steering fluid color is usually pink or red and has a different smell
If you notice that leak is indeed coming from the power steering it’s better to go to a car service and fix this issue as soon as possible.
A stiff steering wheel
If you notice that the steering wheel becomes more and more difficult to handle in a hydraulic power steering, that is because the steering box retains more heat or may lose hydraulic pressure. This is a common problem for a hard to handle steering wheel beside the fluid leak.
This problem also requies imediate fix.
Crackling sounds as you turn the steering wheel
If you hear crackings when turning the steering wheel, that is clear symptom of a failing steering box or rack. Those sounds are made because of the lack of fluid. Because of excess heat, it creates a direct contact between two metal bodies which creates that sound.
If you’re in a turn and hit a pothole you will notice that the sounds amplify.
A smell of burnt fluid
Although not a popular cause, the smell of burnt oil is an essential symptom. As I said above, the distinct odor of the power steering fluid helps you distinguish this fluid from others in your car.
The smell becomes even stronger when the steering box is heated, so you will feel it while driving.
The car tends to pull to one side
If you drive the car on a straight road and see that the car pulls on one side, then this can mean that’s a problem with the steering rack. Although this is a common problem regarding wheel alignment, this can also mean a faulty steering box or steering rack.
Potholes or bumps on the road will feel stronger in the steering wheel
This is another common symptom when the steering box or steering rack fails. As this car part weakens, you will likely feel stronger vibrations in the steering wheel when you hit a pothole or a bump, or you could experience certain shocks during turns.
Check engine error displays on the dashboard.
The “check engine” light could indicate that there is a problem with the steering rack.
The simplest problem is a burnt fuss. All you have to do is replace it and chances are that the problem is solved. If it burns again or it has not been burned from the start, the steering rack must be changed.
Solutions for a bad or failing steering box or steering rack
When dealing with a faulty steering box or rack you will have to either replace it or repair it. The second option comes with some risks.
You also have the option to replace it with a steering box or rack from a car junkyard. But this is a lottery. From my point of view, this is a bad choice, because you don’t know the history of the donor car.
You could either be lucky to get yourself a very good part or you could get a steering box or rack that fails again after sooner than you’d expect.
Can the steering box or rack be repaired?
The answer is yes. There are specialized car repair shops that can fix a bad steering box or rack, but that comes with some risks. Being a complex part, repairing it is not that easy. Search for a repair shop that offers testing and warranty.
How to test a steering box?
Place the car on a smooth road and move the steering wheel from side to side, from bottom to top and vice versa. If you notice that there is a strange sound or a movement between the steering wheel and the steering column, it is important to go to the service for a deeper check.
Pulling and pushing the steering wheel in several directions to identify the loosening of the elastic couplings or joints. The steering problems can also be identified by gently turning the steering wheel from left to right, with the car wheels in the right spot, without moving them when the engine is running. Full turning to the left or to the right is recommended to check for unusual vibrations or noises.
How much does a steering box or steering rack costs?
Usually, a new steering box prices start from $600 and could end up above $1500, plus labor costs that start from $250, depending on what service you choose.