A steering rack or, more correctly, a rack and pinion steering gear is a design that converts the rotation of the steering shaft into a horizontal movement of the rods. The link between the driver who turns the steering wheel and the wheels. Most modern passenger cars have this type of steering mechanism, which replaced the worm gear.
However, this is not a logical continuation of the worm gear. For the first time, a steering rack was installed on cars of the nineteenth century, in a primitive variation of a gear on the steering shaft and a rack interlocked with it.
Later, it was replaced by complex mechanisms, including a worm gear, only at the end of the twentieth century, the designers again returned to the rack and pinion design. The design has become so successful that the modernization continues to this day.
Steering rack device
The connection of the rack with the wheels occurs due to the steering rods, which, with the help of the tips, set the angles of rotation of the wheels.
There are three types of rack and pinion mechanisms:
- Mechanical.
- Hydraulic.
- Electric.
The steering rack layout will vary depending on the type of mechanism, but the general principle will remain the same.
Mechanical steering rack
It is the simplest type of rail, but at the same time the most versatile, because the mechanism is installed on both front-wheel drive and rear-wheel drive vehicles. The turning of the wheels is carried out only with the help of physical strength. A feature of this design is a variable gear ratio. This means that the pitch of the teeth changes from the middle to the edges. When driving at high speeds, when the cornering angles are minimal, the effect of a heavy steering is created due to the large gear ratio. And in parking mode, when the steering wheel is turned to the extreme positions, on the contrary, the gear ratio becomes low and the steering wheel is easy to turn.
The steering rack diagram includes:
- an aluminum crankcase with a cavity with special protection in the form of a rubber corrugation;
- a drive cogwheel or a conventional gear attached to the inside of the housing with a special bearing;
- a spring that tightly presses the rack to the gear, thus ensuring a tight adhesion of the teeth;
- the thrust hinge bush works in the specified interval and provides the required steering rack travel.
Electric steering rack
The principle lies in the operation of an electric motor, which transfers the power from the steering wheel as accurately as possible. The electric booster can be integrated into the rail or located on the steering shaft. This method allows the installation to significantly reduce the cost of construction, while at the same time reduces safety.
The fact is that when the electric motor fails, the control becomes very tough, in fact, uncontrollable. The steering wheel simply does not lend itself, despite the efforts made. However, the steering rack device with an electric motor has a number of advantages that outweigh the disadvantages:
- high efficiency;
- simplicity and compactness;
- immunity to weather conditions;
- lack of working fluids;
- high reliability due to the absence of gaskets, oil seals, tubes;
- efficiency (the electric motor works only when the steering wheel is turned, and turns off at high speed);
- low cost;
- quick return of the steering wheel to neutral position.
Hydraulic steering rack
The principle is to transmit power by means of hydraulic fluid. This ensures precision and ease of driving. Thanks to the hydraulic system, the transmission of road irregularities to the steering wheel is reduced and driving into a hole at speed will not rip out the steering wheel, since the shock will be extinguished by the hydraulic booster. But the high pressure of the fluid at the moment of impact will affect the state of the entire system.
The disadvantages include:
- poor information content of the steering wheel, lack of good feedback;
- poor reliability due to high pressure during operation;
- leakage and regular replacement of oil seals, gaskets, tubes;
- constant operation of the system, even if you stand motionless with a running motor, the pump will circulate liquid in the system;
- repair problems, you have to change the fluid.
Despite a decent number of drawbacks on heavy vehicles, hydraulic steering is worthwhile, since the electric motor is not able to transmit the force that the fluid provides.
Electro-hydraulic steering rack
The logical continuation of the hydraulic rack was the electro-hydraulic one. This is a hybrid system with technology, the device of which is based on hydraulics, similar to that of a power steering, but the pump is driven not by an engine, but by an electric motor. This option eliminated the lack of uninformative feedback. The higher the speed, the less pressure the electric motor creates, giving a stiffer steering feel.
The advantages and disadvantages of the rack and pinion mechanism
- simple small-sized design;
- reliability;
- light weight;
- precise transmission of efforts.
- good transmission of impacts of irregularities in the road surface;
- maintenance intervals (tightening, oil change).
Outcome
The steering rack is one of the most important mechanisms in a car that connects the steering wheel and wheels, and also serves as a connecting link for them. Fast, precise response and power transmission to the wheels is the key to your safety. Therefore, the designers improve the steering rack device every year.
Steering rack, also referred to as power steering gear, is a power unit of the steering mechanism, designed to transfer force from the steering column to the steered wheels.
Types of steering racks
If you look photo, steering rack on different cars, you will notice that these parts are structurally different from each other. At the moment, there are several common types of steering racks, in particular:
- mechanical;
- hydraulic;
- electrical.
The most modern are electrical rails, while the most common at the moment are classic hydraulic and mechanical systems.
Design features
The force applied by the driver is transmitted to the steering column, which is connected to the steering rack through a cardan shaft. Further, through the rods and tips, this force is transmitted to the pivoting levers, through the trunnions connected to the wheels.
In fact, the rack is a gear train. The gear is rigidly attached to the steering shaft, and teeth are placed on the rack itself, to which it clings. Turning the steering wheel, the driver through the gear shifts the rack to the left or right. And already the rack, pressing on the hinges and rods, turns the wheels.
Now on most car models, steering racks are equipped with mechanisms that somewhat facilitate steering wheel rotation. The most popular is. In this case, a pump, a force generating device and a distributor are added to the standard rail. The pump runs on, pumps hydraulic fluid from the expansion tank into the spool valve. This device monitors the force applied to the steering wheel and, as it increases, helps to turn the steering wheel.
Steering rack device: 1. Rack housing; 2. Rake; 3. Steering shaft with worm and bearing; 4. Clamping sleeve (for adjusting the gap of the worm gear); 5. Adjusting nut; 6. Support sleeve on the left side of the rail; 7. Support sleeve on the right side of the rail; 8. Retaining ring (only for the left side); 9. Steering shaft nut; 10. Slider; 11. Slider bushing; 12. Protective metal case; 13. Plastic boot; 14. Retaining ring of the steering shaft nut; 15. Steering shaft cross.
The distributor is based on a torsion bar located on the steering shaft. When the steering wheel does not move, the torsion bar is untwisted, the inlet ports of the distributor are closed, so that the oil flows freely into the expansion tank. When the steering wheel begins to rotate, the torsion bar is twisted, as a result of which, through the spool and channels, the liquid enters the actuator, increasing the pressure behind the actuator piston, or even before it, which creates a force on the piston rigidly fixed to the rack and makes it easier for the driver to turn the steering wheel.
Before we start talking about the types of electric amplifiers and their typical problems, let's say a few words about the algorithm of their operation. Immediately after starting the engine, a self-diagnosis of the system is performed - its operability is confirmed. In the neutral position, the electric motor does not work: the whole system is waiting for active action.
As soon as you start turning the steering wheel, the signal from the steering angle and torque sensor goes to the ECU, which in turn gives the command to the electric motor, which makes your life easier. Moreover, the nature of the operation of the electric booster will be different depending on the speed of the car: in this way, the progressiveness of the operation of the EUR is achieved. After cornering and gradually relieving steering force, the system will return the wheels to neutral position.
Surely, the owners of front-wheel drive cars with a transverse engine have noticed how the car, with an active start, leads a little to the side. This is due to the different lengths of the drive shafts on the right and left sides. So, models with an electric booster can also steer the wheels a little, thereby compensating for the drift. In general, the effort on the steering wheel is completely under the control of the EUR - and therefore it is on his conscience that "emptiness of the steering wheel" and "artificiality of effort", which is so often talked about and which many journalists complain about.
What are electric amplifiers
These systems are divided primarily according to the place of installation of the power unit (electric motor): on the steering column (almost under the steering wheel) or on the steering rack. In the first case, the steering mechanism will be the most common, for example, as in the Nissan Micra, and in the second, an electric motor or drive is integrated into the design. Today, in practice, we will consider a more interesting option with a rail amplifier.
On the steering gear itself, the electric motor can be installed in different ways - either separately or as part of the body of this steering gear. There is also a distinction between the type of rack rod drive: an additional gear wheel or a movable screw-nut connection.
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In the latter case, the electric motor can transmit rotation through a belt drive, or the drive can be direct (as in Lexus GS rails).
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To understand when and how much it is necessary to "help" the driver to turn the steering wheel, the system uses data from several sensors - a torque sensor on the steering gear shaft, a steering wheel position sensor, a crankshaft speed sensor and wheel speed sensors. The only sensor that relates directly to the EUR system is the torque sensor.
More about the device
Now consider three different design options: auxiliary gear steering racks, parallel drive racks and direct drive racks. Each of them has its own pros and cons - now we will outline which ones.
Racks with an additional gear include an electric motor, which, through a worm gear, rotates a gear very similar to the one we rotate through the steering shaft. On the rail itself, in this case, there are two notches of teeth. In this design, everything is not bad - only the friction losses are high: after all, this is a worm gear. With this design, the electric motor often has its own housing.
Rails with parallel drive - this is the name of a mechanism in which rotation from an electric motor through a belt is transmitted to a nut, or, more precisely, to a pair of "screw-nut".
The screw protrudes here a stem with a threaded thread on one side and a notch of teeth on the other.
Balls are placed between the nut and the screw, through which rotation is transmitted - they also act as a bearing. It works like this: when you start turning the steering wheel, an electric motor comes into play, turning the nut in one direction or another, helping you turn the steering wheel.
Direct drive racks are a third option in which the steering rack housing is partly an electric motor housing with the rack stem extending inside it. The rotation from the electric motor is transmitted through the already known pair of "screw-nut".
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So these are the main types of constructs. Communication with the service master allowed us to find out another important feature: there is a fundamental difference between Japanese and European rakes. The Japanese “hide” the electric power steering control unit away from the steering mechanism itself - as a result, a long train of wires for control, communication and diagnostics stretches to the electric motor. Europeans, on the other hand, mount the control unit next to the electric motor or directly on it.
Which approach is correct is hard to say. In the case of the "Japanese", to remove the entire system, you need to pull out a few meters of wiring and find the control unit itself - but in this case the unit is safe. With the European rail, there will be no problems in terms of dismantling: disconnect two or three connectors, unscrew a couple of mounting bolts - and that's it. However, the control unit in such a scheme is subject to various external influences.
Primary diagnostics
The initial diagnostics of a car that entered the service area is based on data received from the owner of the car: for example, a constant knock or only when rotating, a bite on the steering wheel, an uneven effort on the steering wheel or its absence. Based on this, the rail is dismantled and connected to a special stand (we have it MSG MS561) and errors are read. With the help of the stand, they simulate the operation of the engine in various modes and study the operation of the steering mechanism in more detail. This is done in order to localize the malfunction and understand whether the problem lies in the hardware or in the electrics.
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Problems in order
First, let's talk about the mechanical part of the system. Here everything is the same as with other slats: almost any problem is related to the rupture of the anthers of the rail and the ingress of water and dirt into it. Water is inevitable corrosion, and dirt is excessive wear of rubbing surfaces.
Side bushing wear is perhaps the most harmless thing that can happen to a rack rod. Flushing out the lubricant from the screw-nut pair can cause the pair to bite or even jam the steering gear in one position.
In mechanisms with a parallel drive, the ingress of moisture on the belt leads to a sharp increase in its wear and, ultimately, to rupture. A sharply increased effort on the steering wheel is what the driver feels in this case.
Rarely, but it happens that due to moisture, the bearing of an electric motor corrodes - then you will hear the frenzied howl of the latter during operation.
Wear in the gearing of the pinion shaft and rack stem is also a potential cause of boot rupture. But here you can try to cure the disease by tightening the stem stop.
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Asking the master about the effect of water on the electric motor, if the drive is direct, we learned that there can be no special problems with the motor itself - good insulation of the wires does its job.
Having dealt with the mechanics, we turn to the "source of power" - the electrical part. There are not many potential problems here, but almost all of them come with substantial costs.
For example, if the electronic control unit of the system is installed on a rail, then it is often not protected in any way, therefore a pebble that has flown in from somewhere can break the cover of the unit. And even if you notice it immediately (which is unlikely), the block will still have to be sent for replacement. At the same time, when we say "block", we mean the entire rail, because blocks are not supplied separately, and at the moment only modest attempts are being made to repair this element. But all attempts crash against the impregnable wall of lack of software for programming ECU processors.
Failure of the torque sensor is another unpleasant situation on the road. In this case, the EUR “does not understand” with what frequency and effort to help you turn the steering wheel and in which direction.
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The amplifier will not turn off completely, since it will "take" the data from the speed sensor and the steering wheel angle, but the EUR malfunction indicator will light up on the dashboard. Moreover, it may happen that you need to turn the steering wheel to the right, and the electric motor will "turn" it to the left.
The sensors themselves can be analog or digital, therefore they have corresponding problems. Analog ones "suffer" from wear: this is manifested in different efforts on the steering wheel or movement of the mechanism from the central position.
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Digital ones, however, also suffer from wear and tear, but not the sensor itself, but a loop that can corny frayed.
We treat the rail
Mechanical problems with the rod stem are not cured in any way. Corrosion, excessive wear on threads or teeth will send you out to buy a new stem - no grinding or any other processing is provided here. If everything is in order with the rod, and the cause of the knocking was the wear of the side bushing or an increased clearance in the gearing, then the bushing can be replaced without any problems, and the gap can be adjusted by tightening the rod stop (as in the case of hydraulic amplifiers). Actually, there are simply no other solutions to hardware problems.
But with an electrician, as mentioned above, wherever you look, there are only frustrations. If the errors read are related to improper operation, then you can try to remove them - but if they are breakdowns ... Then the solutions are simple, but expensive. Judge for yourself: the slightest crack in the cover of the block is, in most cases, the replacement of the entire steering rack. Corrosion of the electric motor bearing means two ways to solve the problem: replacing the electric motor with a control unit, or again replacing the entire rack assembly. By the way, a complete replacement is a verdict of any authorized dealer: the manufacturer usually simply does not provide for the possibility of repairing and restoring the steering gear with EUR.
And if the drive is direct, and water gets inside, then what will happen to the electric motor? Fortunately, nothing: it will be rinsed with gasoline, dried and sent back to service. Regarding this element of the EUR, the master generally noticed that he had never met any problems associated with the failure of the motor of the system.
A breakdown of the torque sensor is treated by replacing the sensor. The only consolation for a design with an analog gauge can be the possibility of small adjustments (± 1 °) of the EUR. But if the sensor socket is significantly broken, then the adjustment will no longer help.
One of the most common causes of sensor failure is damage to the boot that is installed above it. It begins to rot from constant moisture and eventually collapses, sending the sensor for replacement - if there is such a possibility. If not, then ... You probably already guessed: replacing the rail assembly. But the most offensive thing that can happen is a banal breakage of the connector on the rail, because in this case, too, nothing but replacing the rail assembly will help.
If you are lucky and the rail has been repaired
Upon completion of the work, the rail is assembled and installed on the car.
After installation, it is necessary to initialize or adapt the EUR. This action is extremely important, since it allows you to "teach" the rail to see all sensors and extreme positions. If this is not done, then the electric motor will twist "to the victorious", as a result of which at the end of the stroke the rod will hit with considerable force at close range. After the adaptation is completed, the system will sharply reduce the force 5 degrees to the extreme position, protecting the rod from impact.
The steering rack transfers rotation from the steering wheel to the wheels. It affects handling, and any malfunctions in this unit make the car less obedient. Steering rack elements are subject to natural wear and tear and are subject to shock loads from driving on uneven roads. This leads to the fact that the steering rack of almost every car needs to be replaced or repaired by a mileage of 200–250 thousand km.
8 signs of a faulty steering rack
When driving over bumps and when turning the steering wheel, a knock is heard in the area of the steering rack.
The handling has deteriorated, the car "throws", it is especially acutely felt at high speed.
Rudder free play (backlash) is increased.
The steering wheel turns harder than usual or jerks.
The steering wheel does not return to its original position after turning, you have to turn it with your hands.
The power steering pump is noisy, the sound is amplified when the steering wheel is rotated.
The oil level in the power steering reservoir drops.
Oil leaks are visible on or near the rail.
Suspension elements can knock - ball bearings, steering tips, silent blocks, bushings and stabilizer struts. The wear of these parts leads to poor controllability, an increase in the steering wheel play. The suspension must be checked, defective elements must be replaced.
Heavy rotation of the steering wheel, non-return or slow return to the starting position may be the result of improper adjustment of the rack or violation of wheel alignment. If you have recently adjusted the rack, redo it, but already correctly, check the wheel alignment angles at the service station.
For vehicles with an electric power steering, the cause of a "heavy" steering wheel may be a failure of the electric motor, an open or short circuit, oxidation of contacts in the connectors, a malfunction of the system control unit or blown fuses.
Leakage of fluid from the power steering system and the noise of the power steering pump are connected - oil flows out through worn out oil seals and seals. Through them, air enters the system, due to which the pump makes noise. Inspect the pump housing, hoses and connections; if you find a leak, fix it.
How to determine wear of parts inside the rail?
On a muffled car, shake the steering wheel left and right with a small amplitude. If you hear a knock, repair is needed. If there is an assistant, let him at this time take hold of the steering rod with his hand, so you can more accurately determine where the play is.
Repair or replace?
Replacing a faulty rail with a new one is easier than repairing. But more expensive. Consider the cost of repairing the rail of a 2009 Ford Focus II. The new original rail costs 45,000 rubles. Substitutes offer to buy at a price of 20,000 rubles, but their resource, according to car owners, is unpredictable.
A repair kit for a Ford Focus II rail costs 2,500 rubles, anthers with clamps - 600 rubles. The savings are obvious, but it will take about 2 days to remove, repair and install the unit. For dismantling and installation, a regular set of wrenches is suitable, but in order to disassemble and assemble the rail, you need a special tool, which you will have to buy or make yourself.
Before starting the repair, try to soberly assess your strengths and capabilities, compare the benefits of self-repair and the upcoming labor costs.
Removing the steering rack
Dismantling the rail has its own characteristics for each car, but in general, the procedure is as follows:
Install the front of the car on the supports, remove the wheels.
Press out the steering tips from the steering knuckle pins (use a special puller).
Remove the heat shield of the rail.
For cars with power steering - unscrew the oil supply and return hoses (place a container under the hoses to drain the fluid), for cars with electric power steering - disconnect the connector or remove the steering shaft position sensor.
Remove the bolts securing the steering rack to the subframe or engine shield (depending on the make and model of the car).
Loosen the pinning bolt of the universal joint between the rack and the steering shaft.
Pull the rack in the direction of the steering shaft to release the spline connection (if the rack does not go, it is allowed to knock it down with light hammer blows).
Pull out the rack through the left or right wheel arch (depending on the layout of the engine compartment).
Pressing out the steering tip with a puller
Advice: not in every car you can get the rail just like that - the stretcher can interfere. Removing it completely is long and difficult, try to unscrew only the rear bolts and the engine support, then take the subframe down. This is often enough and the rake is released.
To remove the rack in the Peugeot 308, you need to unscrew the rear bolts of the subframe and take it down, this is easier than removing the entire subframe.
After dismantling, the rail must be cleaned of dirt and washed.
Disassembling the rail
It is better to disassemble and assemble the steering rack clean, without sand and dust. If abrasive particles get inside, the surfaces and seals will quickly wear out, the rack will flow. Fix the rail in a locksmith's vice, if not, put clean cardboard or other material in place of disassembly.
Important: do not clamp the rail too tightly in a vice - its brittle aluminum alloy body may burst or deform.
Steering rack disassembly procedure
Remove the clamps and pull off the anthers of the steering rods.
Securely fix the rack housing and unscrew the steering rods (there are grooves for an open-end wrench on the threaded sleeve).
Unscrew the locknut and nut of the adjusting mechanism, remove the washers and the pressure sleeve from the seat.
Unscrew the drive shaft housing or nut (a special wrench may be needed), remove the shaft from the housing.
Pull out the rack rack.
Take out the sealing collars, bushings and PTFE rings from the rack housing.
The location of the drive shaft and toothed rod in the steering rack
Tip: Before disassembling the rack, mark the position of the toothed rod or measure how much it protrudes from the body on both sides, so that you can reassemble it correctly. Mark the position of the adjusting nut and count the turns as you unscrew it in order to set the pressure sleeve in the correct position after assembly.
Troubleshooting details
The parts of the disassembled rail must be wiped off oil, cleaned of deposits and carefully inspected. Repair kits usually contain only rubber seals and PTFE bushings with rings. This may not be enough for every case.
Carefully inspect the surface of the toothed rod for damage and wear. Pay special attention to the working area - the teeth and the part of the stem that comes into contact with the rings, oil seals and bushings. Any damage, corrosion, risks and scuffing will lead to rapid wear of the seals and leakage of the rack.
Deep corrosion of the rod stem. Such a detail cannot be used.
There should be no cracks, notches, chips or deep wear on the bevel teeth of the drive shaft gear. It is dangerous to install a shaft with such damage - the rack can jam in motion.
A common cause of knocks in the rail is wear of the pressure sleeve. The working surface of the part must be smooth, without traces of punching and scoring. The clamping sleeve is usually not in the rack repair kit, but it can be bought separately for many cars.
Wear of the clamping sleeve - the PTFE insert is pressed through
Severely worn and damaged rail parts cannot be repaired in a garage. If problems are found during troubleshooting, contact specialized service stations for help. There they can restore the shaft and the rod of the rack using professional equipment.
Assembling the rail
Assemble the rail in the reverse order of disassembly. Lubricate the parts with power steering oil before installation so that no scoring occurs on the bushings.
Insert PTFE rings and bushings into the rack housing carefully - the material is fragile and can burst from impacts or great force. For accurate insertion, you can use an appropriately sized socket and extension from the wrench set.
After installing the toothed rod, center it according to the marks made before disassembling, then insert and screw the drive shaft.
Insert the clamping sleeve and washers into the socket, turn the adjusting nut by the required number of turns and turn the mechanism by hand several times from stop to stop (you need to rotate by the drive shaft). If the rack is assembled correctly, the toothed rod should move easily without jamming. Tighten the adjuster locknut.
Tighten the tie rods and install the anthers, squeeze them with special clamps.
Important: do not put plastic ties instead of clamps, they do not provide reliable crimping of the boot, moisture will get into the rail, the stem will rust and damage the cuffs. The rail will flow.
Installing the steering rack
It is better to put the steering rack on the car with an assistant - one starts the rack from the side of the engine compartment, the other directs the cardan joint into the shaft splines from the passenger compartment. The cardan joint can only be put in one position - there is a special casting in the splined joint, which must be combined with the groove on the mating part. Do not immediately tighten the pinch bolt - the cardan joint will take the correct position on the splines after the rail and subframe are finally screwed on.
Install and tighten the steering rack and subframe mounting bolts, then finally tighten the steering shaft universal joint pinch bolt.
Insert the pins of the steering ends into the trunnions and tighten the nuts. Connect the tubes and hoses of the power steering (or wire connectors for the system with EUR). Fill the power steering fluid into the reservoir up to the “maximum” mark.
Install the wheels and, without removing the car from the stands, start bleeding the system (for cars with a power steering).
How to pump the power steering system
Scroll the steering wheel several times from lock to lock with a slight delay in the extreme positions.
Remove the car from the stands, add fluid to the power steering reservoir if the level drops.
Start the engine.
Scroll the steering wheel several times from lock to lock, also with a delay in the extreme positions.
Make sure that the power steering pump does not make noise, add fluid to the tank if the level has dropped and inspect the connections, hoses and power steering tubes for leaks.
Tip: do not rush to install the heat shield, it will be more difficult to inspect the rail during the test ride.
After bleeding, check again the tightness of all threaded connections and make a test drive. Repair of the steering rack can be considered successful if:
The steering wheel has become lighter and "sharper".
The knocking and noises stopped.
The fluid level in the power steering reservoir does not drop.
The rail does not flow.
The car handles well, holds the road confidently.
If everything is in order, reinstall the heat shield.
After repairing the steering rack, be sure to check the alignment at a car service or yourself.
Steering rack repair: do it yourself or at a service station?
Repairing the steering rack yourself in the garage is profitable, but not easy. It will take a tool, time and patience.
Specialized car services offer an alternative to repairing in the garage or buying a new part - a complete restoration of the rail.
The specialists themselves will remove the rail, select the necessary repair kit, and restore problematic elements that are not on sale. If the work described in the article seems difficult, entrust the repair of the rail to professionals.
Steering rack - This is a car unit that is designed to steer the wheels. The driver turns the steering wheel, through special shafts the "turn" is transmitted to the rail, which transmits the force to the wheels. Thus, they are deflected to the desired angle. Thanks to this design, the car can go around obstacles, turn, maneuver, and not move in a straight line.
This unit evolves along with the machine, before it was a rather primitive design, now more and more technologies are being put into control. But to this day, there are only three main types of steering racks. Let's take a closer look.
Steering rack types
- Normal, no amplifiers ... It was used in 70 - 80 years of the last century on 90% of cars. Here, all the steering effort lies with the driver, there are no amplifiers, and therefore it is not always easy to turn the steering wheel.
- Steering rack with GUROM or power steering. In fact, this is the same ordinary rail only a special pump and a closed circuit with oil seals (where a special fluid swings) are added to it, which helps to turn the steering wheel. That is, the driver does not need to put a lot of effort to turn the steering wheel. This is especially valuable on heavy vehicles (trucks, buses and SUVs).
- Steering rack with EURO or electric power steering. This is a dry type of amplifier, no oil is used here, and the principle of operation is completely different. Next to the shaft there is an electric motor with a gear (power comes from the on-board network), which helps to turn the steering wheel. He is given the order by the ECU, he sees where the wheels are deflected and orders the electric motor to help in the turn.
To exaggerate, the types are divided as follows: - conventional mechanics with 100% use of muscular strength, a rail with a hydraulic booster and an electric booster.
How does the steering rack work?
The steering rack of a car is a device, the purpose of which is to convert the driving force during the action on the steering wheel in the car, which is necessary to ensure that the wheels of the car turn.
Today there are three types of steering racks, the operating principle of which is different.
Hydraulic steering rack. It is used in almost all passenger cars that are produced today. Provides a fairly comfortable driving experience, since hydraulic power steering is used, so that the driver needs to make a minimum of effort. Mechanical steering rack. The device of this element is very simple. At one end of the rack, there is a gear mechanism that contacts the toothed rack. The latter interacts with the steering wheel drive.
Electric steering rack. Its difference from its hydraulic counterpart is that hydraulics are not used. To increase the driver's efforts, the car is equipped with a separate electric motor. The design of the steering rack, as well as the principle of its operation, depend on the characteristic features of each car. The steering rack can have an upper or lower position, which also depends on the vehicle model. Overhead steering racks are mounted to the rear of the engine and are attached to the vehicle body. Bottom-mounted steering racks are attached from the bottom, they are connected to the body, subframe or beam.
Troubleshooting the steering rack
Steering rack malfunctions are quite common, since this unit and the entire steering system on domestic roads are exposed to increased loads. Breakage of the rail can be detected independently, guided by a number of signs:
When these symptoms of a rack failure appear, it is recommended not to delay the dismantling of the steering gear for inspection and troubleshooting, in order to minimize repair costs.
- it has become more difficult to rotate the steering wheel, or it periodically bites (difficult rotation is observed only periodically in certain positions of the steering wheel);
- there is a knock of the front suspension, which clearly "gives off to the steering wheel";
- the power steering pump makes noise;
- backlash in steering wheel rotation, which means there is a backlash in the rack;
- leakage of oil from the steering rack, which is often accompanied by a noticeable increase in the steering effort and the noise that occurs during this action.
The manifestation of such signs indicates that steering rack device somewhere it is broken and this mechanism requires diagnostics and further repairs.
Repair features
Even before disassembling the steering mechanism, it is required to conduct a thorough inspection of the rack and all associated units (ball, steering rods, hub bearings, etc.). This will help to localize the problem from the very beginning. Further, the steering gear is completely or partially dismantled and the breakdown is repaired. The rail is a repairable unit, therefore, if it fails, a complete replacement is not always a necessary solution.
Without partial disassembly of the entire mechanism, it is almost never possible to troubleshoot problems associated with the steering racks due to the specifics of the location and connection of this unit.
A corrected steering rack with your own hands is also quite likely, with the exception of the repair of electronic racks that need special adjustment. However, in order to achieve optimum quality, it is always better to trust the job to a specialist and to give preference to replacing the rails instead of repairing them, given the importance and high wear rate of this unit. 
- The condition of the protective anthers must be monitored.
- Do not keep the steering wheel in the extreme position for more than 5 seconds. Do not crank the engine at the extreme position of the steering wheel. This leads to wear of the power steering pump, an increase in the load on the parts of the steering rack, steering gear; contamination of the power steering system, breakdown of the power steering seals.
- In winter, do not twist the steering wheel to drive out of the parking spot immediately after the engine has warmed up. Turn the steering wheel in short, smooth strokes. This is necessary to warm up the oil in the power steering system.
- Personally supervise all operations at the workshop, one way or another affecting the steering elements. Often, when adjusting the camber, the mechanics loosen the boot clamp and forget to tighten it back. Moreover, the work is done with dirty hands! Sand and dirt can ruin a rack and power steering in literally two days, and even faster.
