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Power Steering: What It Is, How It Works And Why It Can Break Down

Power steering has become an intrinsic feature of all vehicles today, even though some developing countries can not yet enjoy everything they want in the new car market. Dating back to the early 1900s, this mechanism has … Read More

Power steering has become an intrinsic feature of all vehicles today, even though some developing countries can not yet enjoy everything they want in the new car market. Dating back to the early 1900s, this mechanism has made steering surprising and easy to steer and a heck for drivers to handle when assist fails.

If you have ever tried to drive a car without power steering, you will know how vital this system is. So here RCC Auto Transport is explaining you everything about Power Steering.

Power steering makes manoeuvres easier, safer and more comfortable for your passengers. Provides the ability to swerve to avoid unexpected road obstacles or intruders, such as animals or other vehicles or pedestrians not paying attention. When it comes to vehicle safety and agility, the power steering should be in good condition. And to the greatest extent, it is, but it is not immune from failure.

The first power steering system in a car was installed in 1876 by Fitts, but little else is known about it. The next one was installed on a Columbia truck in 1903 that employed a separate electric drive to help the driver turn the front wheels. Robert E. Twyford, a Pittsburgh resident, Pennsylvania (United States), integrated a mechanical power steering as part of his patent issued on April 3, 1900, for the first four-wheel-drive system.

Later, Pierce-Arrow Truck Division Engineer Francis W. Davis (1901-1938) began to explore how to facilitate steering and, in 1926, invented and demonstrated the first practical power steering system. Davis moved to General Motors and refined the hydraulic power steering system, but the company calculated that it would be too expensive to produce. The military needs of World War II to facilitate the driving of heavy vehicles increased the need for electrical assistance in armoured vehicles.

It took until 1951 to see how Chrysler Corporation introduced the first power steering system in a mass-production car (Imperial) under the name “Hydraguide” The mechanism of what would eventually end up in Italian hands (FCA) was based on some of Davis’s expired patents. Of course, direct competitors would not be left behind, so GM introduced the first Cadillac (Series 62) with a power steering system using work Davis had done for the company almost 20 years earlier.

How does a power steering work?

After soaking up a bit of history, it’s time to get to know the practical part of this practical mechanism. Power steering is a system that reduces the force (torque) that the driver has to exert on the steering wheel of a car to move the steering. The objective is to help whoever manages the direction to overcome this force. The physical principle behind the system comes from the force that the driver must apply plus that applied by the steering assistance itself, which are equal to that of the wheel’s self-alignment.

Where F are the different forces:    F SELF-ALIGNMENT = F STEERING ASSISTANCE + F DRIVER

This self-aligning force depends on the vehicle and speed: the lower the latter, the more excellent the resistance. And if the weight on the front axle is high ( most cars have the front drive axle, a configuration that places the heaviest mechanical components – engine and gearbox – in front of the axle), you can be convinced that it will make it difficult to move the wheel. Now, not all power steering systems are the same, but they can be grouped into three groups:

  • Hydraulics: Already in disuse for being too heavy and energy-consuming. The hydraulic steering consisted of a pump and an actuator that generated energy and assisted the movement of the wheels.
  • Electrohydraulic: For an extended period, this has been the choice of most car manufacturers, as they required fewer resources to operate correctly than hydraulics, but they kept the feel of what was happening under the wheel. Rather than being a mechanically driven pump, it relies on a separate electric pump and only works when needed.
  • Electrical: it is more compact, lighter, and, consequently, helps reduce fuel consumption. An electric motor in the steering column can be limited in feel –a fact more than contrasted– and performance for hefty vehicles. But one of the advantages of pure electrohydraulic or electric steering is that it is electronically controlled; it can generate available assistance depending on the speed. In this way, driving is more comfortable.
  • Going deeper into explaining how a power steering works, a hydraulic pump supplies a specific volumetric flow of fluid for this purpose through the system.
  • However, since the steering does not need assistance when driving in a straight line or making slight steering movements, the oil is not always in constant motion. The pump runs constantly but uses less energy than other devices; see air conditioning or heated seats.
  • The moment a steering movement is made, part of this flow is directed to the steering work area. There is pressure in the system, and the highest is achieved when it is turned fully in one direction.

At this point, all the flow is directed to the critical areas without the oil flowing directly. At that time, a pump is blocked, and the resulting pressure is regulated with the help of a relief valve. It creates a hiss that can be heard, on some occasions, when parking the car (without music or mothers-in-law next to it).

In this case, the pump provides its maximum performance. But there is another downside to hydraulic steering compared to electromechanical steering. The shaft seal rings can leak after a certain period of operation, requiring a replacement of the steering gear, which is not easy or inexpensive. Since most car manufacturers do not usually have repair steering parts in mind, the entire steering gear may need to be replaced.

Symptoms of bad power steering; Noises when turning the wheel

A squeak/noise when the wheels turn can indicate that the power steering fluid is not working correctly. A drop in the amount of fluid can be an indication that there is a leak in the power steering rack. Replacing the fluid will only fix the problem temporarily unless the leak is repaired.

Steering wheel hard as a stone

If turning the wheel becomes a more difficult task than moving a bag of rocks, you have another indication that the power steering is failing. Possible causes include a low fluid level or a leak in the rack (as described above), or damage to the power steering belt. 

Replacing these straps can vary from one type of car to another.

The steering wheel vibrates at idle.

This symptom surprises some people because it occurs when the car is idling, and the power steering does not work. Steering wheel vibrations are an indication that the belt is damaged, loose, or needs to be replaced.

Types of power steering problems

  • Loss of fluid One of the most common problems that power steering systems have is leaks. The high pressure of the system combined with soft sleeves that carry the fluid makes it relatively susceptible to errors. Low fluid level can cause a squeaky steering pump, and even a loss of fluid pressure can cause steering assistance.
  • Low fluid levels also lead to increased steering pump wear, primarily caused by inadequate lubrication and high fluid temperatures, further accelerating pump wear (next point). It can cause premature wear and tear and can result in one-off failure of the steering system if not corrected. You can easily detect it because you will notice the liquid dripping. Often there is also a squeak that can be heard.
  • Every vehicle has a power steering fluid reservoir with a dipstick attached to the cap. The markers on this illustrate where the fluid should be when the engine is cold and hot. If you find a leak in the hose or the fluid is too low (for a leak, it is understood), the best way to stop it is to replace it with other. If, on the other hand, you find a leak in the steering gear, rack or pump, go to a workshop to seal the leak.
  • Like any other mechanical system, power steering pumps wear out. When it’s time to replace them, they begin to hum or squeak, or they may not make any noise. Either way, low fluid pressure won’t give you as much help when turning the wheel. Diagnosing a pump is extremely difficult, as there is usually no way of knowing its condition if it is not disassembled. In this case, the only option is to replace the pump.
  • Air in the system The air in the power steering system will also reduce the pressure and assist the steering. If you have the correct amount of fluid, air usually enters due to leaks. Replacing liquid lines and checking connections for loose parts or bad O-rings can help seal the system, remove air, and stop it from making noises (if it did).
  • Blockage in the system Obstructions are power steering problems that are also difficult to diagnose. Similar to checking pump pressure, the fact that it is a relatively closed system in and of itself makes it challenging to find clogs if they exist. These are usually due to worn components or dirty steering fluid and can sometimes be removed by bleeding the system.

Cracked or broken accessory strap

Many vehicles use power steering pumps driven by a belt connected to the block’s crankshaft, the well-known accessory belt. One that is in the latter can skid and cause a reduction in fluid pressure produced by the pump, increasing the effort required to operate the steering. A damaged or broken accessory belt can cause an immediate loss of steering assistance, as the pump is no longer functioning by not being driven by the belt.

Cracked or broken cuffs

Everything wears out over time. Components in a car are under stress while driving, and this can cause damage. After a few years, the sleeves associated with the power steering system harden and crack. The sleeves are also close to other hot parts that can wear away from friction with other parts. These problems can cause holes or cracks that sometimes cause power steering fluid to leak.

As with all car problems, acting early is the best way to avoid complications and dangers on the road. Power steering is a vital part of a vehicle’s systems and helps maintain a steady course. Although you can drive safely without their help, you may find that leaving repairs for too long means you could end up paying a costly repair bill.

Author: admin