Steering rack scheme of work. Steering rack: device, principle of operation and main malfunctions. Faults and repair of the steering rack
steering rack transmits rotation from the steering wheel to the wheels. It affects handling, and any malfunction of this node makes the car less obedient. Steering rack components are subject to natural wear and tear and impact loads from driving on rough roads. This leads to the fact that by the mileage of 200-250 thousand km, the steering rack of almost every car needs to be replaced or repaired.
8 signs of a bad steering rack
When driving over bumps and when turning the steering wheel, a knock is heard in the area of \u200b\u200bthe steering rack.
Handling has deteriorated, the car “throws”, this is especially acute on high speed.
The free play of the steering wheel (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 by hand.
The power steering pump is noisy, the sound intensifies 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 joints, steering tips, silent blocks, bushings and stabilizer struts. The wear of these parts leads to poor handling, increased 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 its original position may be the result of incorrect adjustment of the rack or a violation of the alignment of the wheels. If you have recently adjusted the rail, redo it, but already correctly, check the wheel alignment at the service station.
For vehicles with electric power steering, the cause of a “heavy” steering wheel may be a motor failure, an open or shorted circuit, oxidation of contacts in the connectors, a malfunction of the system control unit, or blown fuses.
Fluid leakage from the power steering system and the noise of the power steering pump are connected - oil flows out through worn 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 the wear of parts inside the rail?
With the car turned off, shake the steering wheel left and right with a small amplitude. If a knock is heard, it needs repair. If there is an assistant, let him at this time take his hand on the steering rod, so you can more accurately determine where the backlash is.
Repair or change?
Replacing a faulty rail with a new one is easier than repairing it. But more expensive. Consider the cost of repairing the rail ford car Focus II 2009 release. A 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.
Repair kit for rail Ford Focus II 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 to disassemble and assemble the rail, you need a special tool that you will have to buy or make yourself.
Before starting repairs, try to soberly assess your strengths and capabilities, compare the benefits of self repair and future labor costs.
Removing the steering rack
Dismantling the rail has its own characteristics for each car, but in general, the procedure is as follows:
Place the front of the car on jack stands and remove the wheels.
Press the steering tips out of the pins knuckle(use a special puller).
Remove the rail heat shield.
For cars with hydraulic booster - unscrew the oil supply and return hoses (substitute a container under the hoses to drain the liquid), for cars with electric booster - disconnect the connector or remove the steering shaft position sensor.
Unscrew the bolts securing the steering rack to the subframe or motor shield (depending on the make and model of the car).
Loosen the coupling bolt of the cardan connection of the rack with 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 blows of a hammer).
Pull out the rail through the left or right wheel arch (depending on the layout of the engine compartment).
Pressing out the steering tip with a puller
Tip: not in every car you can get the rail just like that - the subframe can interfere. Removing it completely is long and difficult, try unscrewing only the rear bolts and the engine mount, then take the subframe down. Often this is 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 subframe completely.
After dismantling, the rail must be cleaned of dirt and washed.
Rail disassembly
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 wear out quickly, the rail will leak. Fix the rail in a metal vise, if there are none, place clean cardboard or other material on the disassembly site.
Important: do not clamp the rail in a vise too hard - its body made of brittle aluminum alloy 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 on the threaded coupling for an open-end wrench).
Unscrew the lock nut and the nut of the adjusting mechanism, remove the washers and the clamping sleeve from the seat.
Unscrew the housing or drive shaft nut (you may need a special wrench), remove the shaft from the housing.
Pull out the gear rod of the rack.
Remove the sealing cuffs, bushings and fluoroplastic rings from the rack housing.
The location of the drive shaft and gear rod in the steering rack
Tip: before disassembling the rail, mark the position of the toothed rod or measure how much it protrudes from the body on both sides, so that you can assemble it correctly later. Mark the position of the adjusting nut and count the turns as it is loosened to ensure that the clamping sleeve is in the correct position after assembly.
Troubleshooting parts
The parts of the disassembled rail must be wiped of oil, cleaned of deposits and carefully inspected. Repair kits usually only come with rubber seals and PTFE bushings with rings. This may not be sufficient for every case.
Carefully inspect the surface of the toothed rod - it should not be damaged or worn. Special attention give the working area - the teeth and the part of the stem that comes into contact with the rings, seals and bushings. Any damage, corrosion, scratches and scuffs will result in rapid wear seals and rack leaks.
Deep corrosion of the rack rod. Such a detail cannot be placed.
On the oblique teeth of the drive shaft gear, there should be no cracks, notches, chips and deep wear. It is dangerous to install a shaft with such damage - the rail can jam in motion.
A common cause of knocks in the rail is the wear of the clamping sleeve. The working surface of the part must be smooth, without traces of punching and scuffing. The clamping sleeve is usually not included in the rack repair kit, but for many cars it can be purchased separately.
Pressure sleeve wear - fluoroplastic insert is pressed through
Heavily worn and damaged rail parts cannot be restored in a garage. If problems are found during troubleshooting, contact specialized service stations for help. There they can restore the shaft and rod of the rack using professional equipment.
Rail assembly
Assemble the rail in the reverse order of disassembly. Lubricate the parts with power steering oil before installation so that scoring does not form on the bushings.
Insert fluoroplastic rings and bushings into the rail body carefully - the material is fragile and can burst from impact or great effort. For accurate pressing, you can use the socket head and extension right size from a set of keys.
After installing the toothed rod, center it on the marks made before disassembly, then insert and screw the drive shaft.
Insert the clamping sleeve and washers into the socket, tighten the adjusting nut to the required number of turns and turn the mechanism by hand several times from lock to lock (you need to rotate by the drive shaft). If the rack is assembled correctly, the toothed rod should move easily, without jamming. Tighten the adjustment locknut.
Tighten the steering rods and install the anthers, crimp them with special clamps.
Important: do not put plastic ties instead of clamps, they do not provide reliable crimping of the anther, moisture will get inside the rail, the stem will rust and damage the cuffs. The rail will leak.
Steering rack installation
It is better to put the steering rack on the car with an assistant - one starts the rack from the engine compartment, the other directs the universal joint into the splines of the shaft from the passenger compartment. Cardan joint can be put in only one position - there is a special casting in the spline connection, which must be combined with the groove on the counterpart. Do not tighten the tie bolt immediately - the universal 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 cardan coupling pinch bolt.
Insert the steering pins into the pins and tighten the nuts. Attach power steering tubes and hoses (or wire connectors for a system with EUR). Pour 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 hydraulic booster).
How to bleed 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 has dropped.
Start the motor.
Scroll the steering wheel from lock to lock several times, also with a delay in the extreme positions.
Make sure that the power steering pump is not noisy, add fluid to the tank if the level has dropped and inspect the connections, hoses and power steering pipes for leakage.
Tip: do not rush to install the heat shield, it will make it more difficult to inspect the rail during the test drive.
After pumping, check once again the tightness of all threaded connections and make a test drive. Steering rack repair can be considered successful if:
The steering wheel has become lighter and "sharper".
The knocks and noises stopped.
The fluid level in the power steering reservoir does not drop.
The rail is not flowing.
The car handles well, confidently holds the road.
If everything is in order, reinstall the heat shield.
After repairing the steering rack, be sure to check the alignment in a car service or on your own.
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 rack.
Specialists themselves will remove the rail, select the necessary repair kit, restore problematic elements that are not on sale. If the work described in the article seems complicated, trust the rail repair to professionals.
Power steering (hereinafter referred to as power steering) in a car is a system designed to reduce the effort applied to the steering during a maneuver. Initially, such systems were equipped with agricultural and cargo vehicles.
Since the beginning of the 70s, power steering began to be installed on cars. Not the last role in this was played by the fact that women were increasingly acting as drivers.
In addition to providing comfort when driving, power steering allows you to:
- reduce the diameter (dimensions) of the steering wheel;
- change ratio steering shaft-rack systems, providing greater maneuverability during a turn;
- automate the vehicle control system.
Given that steering is the second factor in traffic safety after brake system, reliability, information content, and other power steering parameters are subject to high requirements. Special attention should be paid to the operation and maintenance of this system.
Types of power steering
Initially, power steering was installed on passenger vehicles, made according to a scheme similar to amplifiers installed on heavy vehicles. They have significant disadvantage: As the vehicle speed increases, a smaller steering angle and applied force are required to make a safe maneuver. At high speed, the road-steering feedback is significantly reduced, the driver stops “feeling” the road. In slippery conditions, the vehicle may lose control.
To overcome this problem, a rack with variable gear ratio. Such a rail is installed on the VAZ 2110. It has a large gear ratio at small steering angles. This usually corresponds to high speeds and small turning angles where little force is required. The gear ratio decreases towards the "edges", that is, at large maneuvering angles, which are possible at low speeds. The use of this design did not eliminate all controllability problems.
Video - types of steering racks, how power steering and EUR differ:
Manufacturers have developed electric power steering, adding to the standard circuit an electrovalve with electronic system management. EGUR to the maximum extent combines the information content of the steering wheel and comfortable driving conditions.
In some car models, the power steering pump is rotated by an electric motor drive. In such cases, the hydraulic booster works even when the engine is not running.
V modern cars are increasingly being installed electric power steering. Their significant drawback is complete dependence on the serviceability and reliability of electronics. In the event of failure of any of the electronic components, drives, even a fuse, the efficiency of the electric power steering becomes zero, controllability deteriorates sharply.
How power steering works
The basic diagram of the power steering rack device is shown in the figure:
While the engine is running internal combustion the drive of the power steering oil pump, which is kinematically connected to the crankshaft, rotates. If wheel is in the center position, the oil recirculates through the hydraulic system effortlessly through check valve. The torsion bar, which acts as a follower, responds to the steering wheel. It drives the distributor spool. It communicates the main injection channel with the right or left cavities of the power cylinders. The latter help to turn the wheels of the car.
In the extreme positions of the steering wheel, safety valves prevent excessive pressure in the system, bypassing oil into the recirculation channel.
In the electric power steering, an electrovalve is installed, controlled by an electronic control unit (ECU). The power steering ECU, guided by the readings of the sensors for the steering angle, vehicle speed, crankshaft, regulates the closing of the valve. Thus, depending on the speed of the car, other indicators, the degree of power steering amplification is regulated, the information content of the steering is controlled.
Symptoms and Possible Causes
During the operation of the car, the following signs indicate a malfunctioning power steering:
1. Steering wheel kickback. Usually occurs when the power steering pump malfunctions or the drive belt is loose.
2. Great effort when turning the steering wheel. The reason may be: low fluid level, worn power steering pump, system airiness.
3. Big efforts in the area of the middle position of the steering wheel. The main reason is the mechanical wear of the rail.
4. Increased effort to one side. Cause: Worn seals.
5. Turning the steering wheel quickly takes effort. Possible causes: air, pump malfunction, small idling engine.
6. Noise. Causes: low fluid level, leak in the system.
7. Vibration. It often happens when tires are damaged, the brake system malfunctions. In the power steering system, air can enter the hydraulics.
The main malfunctions of steering racks with hydraulic booster, their elimination and repair
During operation, the power steering rack system requires constant inspection, maintenance and repair (if necessary). The most common system failures include:
1.Flow
Oil seal leakage is most often caused by corrosion in the event that water enters the shaft, which, as rust appears on it, destroys the working surface of the oil seal. Such a malfunction is possible when the anther is destroyed, caused by mechanical stress or natural wear and tear.
Repair consists in restoring the integrity of the shaft, removing traces of corrosion (usually the shaft is polished). After that, a new oil seal is installed with the appropriate mounting dimensions.
Leakage of hydraulic hoses is caused by high pressure in the system (100 atmospheres or more), wear of hoses, especially at the junctions of rubber and metal elements of high pressure hoses. Usually a hose replacement is required, but there are workshops that repress the connections.
2.Knock
It may occur for reasons:
- breakage or abrasion of the central tooth of the rack;
- wear of the support sleeve;
- clamping nut malfunctions.
Rack tightening in case of wear of the central tooth does not work. The play may be less, but since the other teeth are less worn (increased wear of the central tooth is due to the fact that the steering wheel has been in the middle position for more time), the steering wheel may not return from the extreme positions due to pinching.
Video - about the resource of the steering rack with hydraulic booster:
The support bushings are strongly destroyed when driving on uneven road surfaces. Majority rack mechanisms foreign cars are not designed for Russian roads.
3.tight steering wheel
If the steering wheel turns with force only in one direction, most likely, the o-ring in the distributor housing passes fluid under pressure. This may be the result of dirt or dust getting into the system, which over time makes grooves. The liquid does not enter the hydraulic cylinder, but goes directly to the expander tank. Repair can be done by grinding working area and replacement of the sealing ring.
If the steering wheel turns tight in both directions, there may be several reasons:
- malfunction of the piston Teflon ring;
- grooves in two chambers of the distributor;
- worn working pair of the pump;
- torsion failure.
To diagnose a specific malfunction, disassembly of the mechanism and diagnostics of the components are required. In most cases, specialist assistance will be required.
Checking the performance of the power steering pump
To check the operation of the power steering pump, a special pressure gauge and adapter blocks are required. Check sequence:
- an adapter block with a pressure gauge is installed in the gap hydraulic system pump outlet hose;
- the engine starts, runs at idle for a couple of minutes;
- the steering wheel is turned several times to the right and left to achieve operating temperature power steering fluids;
- the pump pressure is measured with the shut-off valve open, which must be at least 1500 kPa;
- for a short time ( no more than five seconds!) shut-off valve closes;
- with the shut-off valve closed, the pressure must be at least 6500 kPa.
Recommendations for power steering and rack and pinion to last longer
Hello dear car enthusiasts! The principle of rack and pinion power transmission is not the first time used in the automotive industry in the form of a steering rack. Cremalier (French crémaillère) - one of many types mechanical transmission, which converts translational motion into rotational.
Remember the old, folding cameras that used rack and pinion to focus. But, we are talking about the steering rack of the car.
The steering rack of a car has long been an integral part of the steering. And. on almost all modern cars, a steering rack is used. This does not exclude the use of such types of steering mechanism as: worm gear or screw-ball nut.
Car steering rack device
So, we have already understood that the steering rack of a car is a mechanical device that converts the driver's effort when acting on the steering wheel, which is required to control the car (turning the wheels).
According to the principle of operation, steering racks are divided into three main types:
- Mechanical steering rack - has the simplest device. The gear mechanism located at the end of the steering column interacts with the gear rack, which, in turn, is connected to the steering gear (trapeze from).
- Hydraulic steering rack - installed on most modern cars. Carries out the most convenient and easy driving by connecting the power steering (power steering), which increases the effort applied by the driver.
- An electric steering rack differs from a hydraulic steering rack in that it does not have hydraulics, and the driver's efforts when steering the steering wheel are increased by an electric motor.
The principle of the steering rack arrangement differs only in the design features of the car brand.
The location of the steering rack may also be different depending on the brand of car:
- Top location - the steering rack is attached to the body and is located behind the engine.
- Bottom location - the steering rack is attached to the subframe, body or beam, from below.
Steering rack design (on the example of a gear rack)
- Carter. It is usually made from aluminum alloy. It has a cavity inside, which is protected by a corrugated cover.
- Drive gear mounted in the crankcase on bearings.
- The rack is pressed against the gear by a spring in order to ensure backlash-free engagement of the gear and rack teeth.
- The restrictive ring on one side and the tie rod bushing on the other limit the travel of the rack in the required range.
This scheme of the steering rack has a small gear ratio and allows you to quickly control the wheel in the right direction.
By the way, the designers of the BMW concern improved the steering rack by connecting it to the planetary mechanism. This scheme of the steering rack allows you to change the gear ratio of the gear depending on the speed of the car.
The principle of operation of the steering rack with hydraulic booster
So, let's find out in more detail why the steering wheel with power steering is spinning so easily. An integrated amplifier is when it is connected to the steering rack actuating mechanism power steering.
The power steering pump is driven by the engine using gears: belt or gear. It supplies high pressure hydraulic fluid to the spool valve. The spool valve is built into the crankcase (body) of the steering rack.
The main task of the spool valve is to control the force on the steering wheel and the dosage of hydraulic fluid to turn the steering rack. The dosing device, as a rule, is a torsion bar, which is built into the section of the rack steering shaft.
During parking or driving in the forward direction, there is no force on the steering rack. This means that the metering channels of the spool valve are blocked, and the oil is in the reservoir.
When you turn the steering wheel, the resistance of the wheels begins. At the same time, the torsion bar begins to twist: the greater the force on the steering wheel, the stronger. At this time, the spool valve opens the channels and supplies hydraulic fluid to the actuator - the steering rack. Here the oil is distributed in the right direction and pushes the rail.
Taking into account the fact that the steering rack is in constant intensive use, it is advisable for you, as a driver, to systematically monitor the health of its elements: anthers, seals, tubes.
It is not necessary to constantly climb under the car for this. Do not be lazy to visually check for oil leaks under the car.
Not so long ago, automakers allowed the repair of mechanisms, sold original spare parts and developed recovery technologies. However, later the shop was closed, citing a security threat. Although no fundamental changes have been made to the design and manufacturing technology of steering racks. Fortunately, there is still an alternative to costly replacement of the node due to its leak or knocking. With a qualified approach, the rails are successfully repaired without any safety hazard.
STICKS IN THE WHEELS
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Steering gear seals are of two types. Power cuffs seal the rail - they are designed to work under high pressure: up to 150–200 bar. The steering shaft seal is a conventional stuffing box that can withstand ten times less pressure.Steering gear seals are of two types. Power cuffs seal the rail - they are designed to work under high pressure: up to 150–200 bar. The steering shaft seal is a conventional stuffing box that can withstand ten times less pressure.
Around 2005, almost all automakers changed their policy dramatically - steering racks were declared non-repairable. The sale of original spare parts and access to information about the technology for restoring nodes were covered. However, this did not put an end to the repair industry. For most vehicles, steering gears are made by large third-party manufacturers such as ZF. Therefore, original spare parts remain available and Technical information. In addition, no one canceled the unification. Often, parts from other cars from the early 2000s are suitable for fresh models from one automaker. In addition, there are manufacturers specializing in the same oil seals and bushings. According to their catalogs, it is not difficult to choose a spare part of the required type and size - nominal or repair. So while you can fix almost any rail.
Hidden threat
The real scourge of all steering rack and pinion mechanisms is corrosion. The reason for it is mainly unskilled service. Often, when replacing steering rods, servicemen fix their anthers with universal plastic clamps - this is much easier than having to suffer with the installation of regular, metal ones. But the plastic collar, no matter how you tighten it, does not provide complete tightness of the anther, which is crucial for the health of the mechanism.
During the operation of the rack, the anthers of the steering rods are alternately compressed and unclenched, due to which there is a movement of air inside the assembly. Without such ventilation, each anther is excessively deformed, and this is fraught with damage. For air circulation, most manufacturers make grooves of various types on the rack. If plastic clamps are installed, one of the anthers sucks in warm air from the engine compartment, and the other releases it back. When passing through the steering mechanism, the air actively cools down (after all, the unit is on the subframe close to the ground) - condensation forms. Six months is enough for the rail to begin to rust.
111–1
Steering shaft corrosion makes itself felt earlier on power steering. Due to work on a rough surface, seals begin to wear out and leak quickly. On steering racks with an electromechanical amplifier, it is more difficult to recognize the onset of the disease. When it comes to tangible malfunctions - knocks and backlashes, corrosion will already have time to cause irreparable harm to the gear rack. In advanced cases, it affects teeth that cannot be repaired. The teeth have a complex profile and high surface hardening, and it is correct to restore them after any machining almost impossible.
Corrosion of the remaining surfaces of the rails is fought by three methods: grinding, grinding to the repair diameter and zavtulivaniye. Grinding is done when the rust is surface and the total reduction in the diameter of the rail does not exceed 0.1 mm. In this case, spare parts (seals and a support sleeve) of nominal size are used. With such an increase in the gap, there will be no leaks and knocks.
With deeper corrosion, it is permissible to painlessly grind the gear rack by no more than 0.5 mm. This is the recommendation of most manufacturers. These parts are usually hardened to a depth of about 1.5 mm. After all, they must work reliably under oil pressure up to 150 bar. With such a significant reduction in diameter, spare parts are used repair size. Oil seals are selected from catalogs, and bushings sometimes have to be made.
And here is a curious technology for eradicating more severe rust. The gear rack is machined and, using a special compound, a stainless steel pipe is pressed - this material has sufficient strength. Then the rail is again turned and polished to the nominal diameter. The technology is complex and has many pitfalls.
It happens due to design features corrodes the input steering shaft of the rack. Usually the shaft is at an angle of about 45º, and in the place where it passes through the engine shield, a kind of cup is formed. On many machines, water from the street constantly gets into it, because of which the shaft begins to rust. Corrosion reaches the stuffing box, causing it premature wear. Hydraulic racks will announce a leak, and electromechanical ones, again, are silent to the last. The treatment is similar: the shaft is machined and a repair gland is selected for the new diameter. The depth of processing is not of fundamental importance, because metal with special mechanical properties is not used for the manufacture of this part. However, it is rare when more than 1 mm is removed.
I have already talked about Fiat electric power steering systems. Fiat uses electric power steering, located directly on the steering rack. There is an advantage here: the system is under the “protection” of the cabin, that is, all electrics, electronics, gearbox, drive are located in the cabin. Among the shortcomings: it requires a lot of free space in the steering rack area; increased load on the steering gear. Recently, electric power steering has become widespread, on which the drive with the gearbox is located directly on the steering rack.
Disadvantages and advantages of electric rails
Main disadvantages:
- actuators are located in engine compartment where there is a high probability of ingress of foreign liquids and dirt;
- complication of the already capricious design of rails;
- the electrical wiring of the electric amplifier is in extremely unpleasant climatic conditions.
The advantages of this design:
- free space in the steering column area, which increases the safety of the driver in case of an accident;
- all the kinematics of the power steering is concentrated in one place - on the rail;
- reduction in the total mass of the steering;
- the possibility of prompt repair by aggregate replacement.
Principle of operation
In the middle position of the steering wheel, the steering position sensors form a zero signal to the electronic power steering control unit. No voltage is supplied to the drives, the rail remains in the neutral (zero) position. When the steering wheel is turned in one of the directions, the angular displacement sensors form a control signal to the control unit, which generates control currents for the electric drive, which facilitates the movement of the wheels in the required direction. At the end of the maneuver, the control unit returns the mechanism to its original position.
Structurally, electric rails are currently made in the following versions:
- rails with parallel drive;
- rails with direct drive;
- electric rails with an additional gear.
According to the design, the drive motor can be mounted directly on the rail:
or mounted on a rail as an additional mechanism.
The power steering electronics are quite complex. When processing information about the required steering force, it uses signals from numerous sensors, which are not necessarily electric power steering sensors, for example:
- vehicle speed sensor;
- crankshaft speed sensor;
- wheel speed sensors.
This is necessary so that the steering wheel is more informative. It is one thing when the wheels turn at a speed of 5 km / h, the other - at a speed of 100 km / h. At high speed, in the absence of "feedback" steering, even slight angular displacement of the wheels can lead to an emergency. Therefore, a malfunction of the electric power steering system, especially its electronic part, is fraught with serious consequences.
Communication with sensors of other vehicle systems, control units is organized via the CAN bus. CAN bus failure is common cause failure of the electric power steering system.
Manufacturers territorially install control units in different places. For example, Asians prefer to install control units (electronics) away from the rack electric drive. In this case, they are guided by the fact that the electronics in this case are more protected from pollution, dust, water, oils. But there are also disadvantages:
- a sufficiently powerful electrical wiring goes directly to the electric drive;
- signal wires of the sensors can be damaged, resulting in a definite loss of inoperability.
Quite the opposite is done by European manufacturers who install control units directly on the drive, that is, on the design of the electric rail. I think they rely on the quality of their roads. From this point of view, I would choose the Asian option. But from the point of view of repair, the European rail is better, on which everything is concentrated in a single place: remove the rail - and mess with it.
The main signs and causes of the malfunction
The main signs of a malfunctioning electrical rails are:
1. Jamming or jamming of the rack. Such a malfunction is usually associated with damage to the anther. In this case, dust gets into the area of the teeth, which, mixed with moisture, turns into an excellent abrasive, which with every minute of movement (especially in the urban cycle) slowly “eats” the teeth. After several thousand kilometers, the teeth are so worn out that the result is visible without a microscope. There is only one way out: replacement.
Repairing the control unit for the electric belt booster is a troublesome business. If the firmware has flown, then it is almost impossible to find it, except perhaps from professionals in their field.
Electric rail adaptation
After repair or maintenance of the electric rack, it must be adapted again, otherwise the steering wheel and rack will work with an angular displacement, and the error signal will dashboard will not be deleted. This can only be done with diagnostic equipment, by manipulating the steering wheel to the extreme positions in accordance with the instructions given by the diagnostic scanner.
- Regularly check the condition of the rail anthers.
- If an electric amplifier error message appears, immediately begin troubleshooting.
- If possible, turn the steering wheel to extreme positions less often.
- Do not leave the car with the wheels turned out for a long time.
