The overwhelming majority of motorists have encountered in their practice one rather unpleasant phenomenon - steering wheel vibration. Symptoms that characterize this phenomenon are quite diverse, since vibrational vibrations can occur when the speed of the car changes, during its acceleration or deceleration. In addition, they can be either periodic or permanent.
Then remove all traces of rust around wheel studs and hubs using a scraper, wire brush or soft abrasive wheel. Thoroughly clean the rotor mounting surface inside the rotor stem using an abrasive pad or wheel. After twisting wheel nuts the final travel on the wheel bearings and the runout on the brake rotor should be checked with the dial indicator. Most wheel bearings should have less than 002 inches of play end and spin quietly and smoothly. The upper runout point must be marked on the rotor and indexed onto the wheel stud or the hub itself.
Despite the seeming insignificance of this phenomenon in terms of security road traffic(hereinafter referred to as road safety), it is a sign of serious malfunctions in units, assemblies and systems vehicle... And this is already a serious threat to road safety.
In this article, we will consider in detail only one of the options for vibration of the steering wheel - vibrations that occur during braking of the vehicle. Our choice is predetermined by the seriousness of the reasons behind this unpleasant phenomenon.
For diagnostic purposes, remove the rotor and reinstall it 180 degrees from its original position. If the runout is nearly the same, the runout condition is caused by the rotor. If the runout varies greatly, the runout condition is caused by the wheel bearing hub.
If the runout is within specifications, the rotor must be removed and its thickness measured at a minimum of eight different points in the center of the rotor surface. Off-road Brake Lathes Mounting the rotor on a brake lathe outside the vehicle is an important part of rotor maintenance. In short, the upper runout point indexed on the rotor must be the same high runout point as indicated by the brake lathe.
Causes of steering vibration
So, let's start with the reasons, the consequence of which is the appearance of vibration processes on the steering wheel. There are several of them, as mentioned above, but all of them (at least the overwhelming majority of them) are symptoms of malfunctions of the braking system (components, assemblies):
If the high points differ significantly, either the wheel hub or the brake lathe has excessive runout. In any case, the runout of the face lathe should be checked periodically using the dial indicator. The tolerance should be nearly zero at the rotor mounting point.
Likewise, all hub adapters and other centering lights should be checked for inaccuracies or damage. In many cases, a curved turning column or worn out bearings will actually increase rather than reduce minor cases of rotor runout.
Violation of mass characteristics and geometric shapes wheel rims and brake pads. Dirt builds up on brake discs, changing their weight and shape. This is especially true for cars with open-type "alloy" discs.
Uneven wear of elements of the brake system (brake discs, pads). Most in an efficient way elimination of vibration phenomena on the steering wheel in this case is to replace the brake pads and brake discs new. However, there is also a "budget" method of elimination, which consists in grinding the brake discs. However, it is not always applicable due to structural features and geometrical dimensions; moreover, it is less effective.
Carcass on Automotive While tapered spacers are available for many applications to correct wheel hub runout, the fastest and most definitive way to fix minor amounts of hub hub is to turn the rotor into a car.
Causes of vibration on the brake pedal
However, excessive hub runout should be avoided to avoid machining excess headroom from new rotors. Despite the fact that some import manufacturers allow the use of caliper lathes on their machines, most of them recommend modern lathes that drive rotors independently of the calipers.
Deformation damage to the hub or other suspension elements of the vehicle, which usually occurs as a result of collisions with various obstacles (pit, "lying policeman", road curb, etc.). These malfunctions are diagnosed on a suspended vehicle. Eliminated by replacing deformed elements with new ones.
Completion While the rotary finish has more to do with keeping the brakes quiet than preventing pedal ripple, keep in mind that it is especially important to use a fine feed to reduce ripped metal during machining.
Can the problem be ignored?
Remaining ripped metal is removed by applying a non-directional "cross-stroke" to the rotor with finishing stones or an abrasive pad. Wash the rotor thoroughly with soapy water and dry with a paper towel to remove any metal particles. The brake alarm is the vibration that you feel through wheel when you hit the brakes. Brake alarms are caused by problems with the brake discs. Namely when the brake discs were affected by the change in disc thickness. This refers to uneven wear on the brake discs and is the result of rotor failure.
In addition to the reasons for the occurrence of vibration processes on the steering wheel, mentioned above and which, in fact, are the main ones, there are several more "sources" that ensure the appearance of this process:
- Previous replacement of brake system elements (pads, caliper, brake disk etc.). Low quality"Non-original" spare parts produced on non-standard equipment - these are the main characteristics that lead to "beating" of the steering wheel.
Attention! When choosing a new ("non-original") brake disc, compare it performance characteristics, especially the radial runout, with the parameters specified by the manufacturer of your vehicle.
If your brake discs are unevenly worn, brake pads come into contact with flat spots on the surface of the rotor, which causes vibration, which we cause by shaking the brake. This uneven disc wear can be the result of a number of factors. For example, brake calipers are not working properly, rotors were not installed properly, or proper bedding was not applied if new brake pads were installed.
How do we fix brake shake if it becomes obvious? First, the source of the problem must be isolated. Typically, when a shudder is felt through the steering wheel, it indicates that the front rotors need to be looked at. If a jittery pulsation is felt through the brake pedal, this usually indicates a problem with the rear brake rotors.
The low quality of friction materials can lead to violations of the contact process of the working surfaces and, as a consequence, the occurrence of oscillations of the radial runout of an unacceptable level.
Violation of the geometric shape (curvature) of the brake disc, resulting from a violation of the thermal equilibrium of the element. This phenomenon, as a rule, occurs as a result of the ingress of cold water from a deep puddle or snow slurry on the red-hot metal of the brake disc. The heating of the disc to abnormally high temperatures not provided for by the technology occurs as a result of its (disc) wedging by other elements (caliper guides, piston, etc.).
How do we fix brake shake? Brake calipers that don't work the way they should can also contribute to brake shake. If the caliper holds the pad against the disc when the brakes are not applied, it can cause improper disc wear. If so, then trapped sliding pins in the caliper are usually the culprit. Otherwise, if the problem goes further than the sliding contacts, the calipers may need to be rebuilt or replaced. Another common source of brake jolt problems is an uneven mounting surface on the face of the hub.
Violation of the angle of deflection of the brake disc relative to the hub.
Poor installation (poorly tightened fastening nuts) of the brake disc and hub.
Contact with sand and fine debris on the working surfaces (typical for the autumn-winter period). A symptom of this phenomenon, along with vibrational vibrations, is an annoying grinding noise in the area of the wheels. Eliminated by thorough washing of each individual element in conjunction with cleaning with a wire brush.
Irregular deposits of rust and scale can build up over time on the surface of the hub, which in turn creates an uneven surface for the disc to be mounted on. This should be a common practice when replacing or replacing brake discs to prevent any occurrence of brake shake in the future.
When installing a new set of brake pads, it is important to install them correctly. Adapting new brakes to abuse without keeping an eye on bedding in any way can result in severe heatstroke, which can be a major cause of uneven wear. Also, a small detail, but it is worth paying attention to your wheel nuts.
Summarizing the above, we focus the reader's attention on the main points:
The occurrence of oscillatory movements transmitted to the driver through the steering wheel during the deceleration of the vehicle indicates the presence of malfunctions of the elements included in the brake system, more precisely in its front circuit: brake disc, caliper, pads and their friction elements.
Tightening the wheel nut torque evenly and according to manufacturer's specification using a quality torque wrench can help prevent rotor failure. When it comes to your brakes, it's important to keep them in top condition. At the end of the day, this is the only thing that slows you down.
Several different problems can cause a car or steering wheel to shake during braking, but almost all of them are related to the rotors. Whatever the reason, it's important to get the problem resolved quickly. Vehicle brakes are available as disc or drum system. They both use resistance and friction to get the job done. Drum brakes placed in a round drum rotating with the wheel. The drum has a set of shoes that are pressed against the drum when the brake pedal is pressed.
An objective assessment of the cause of the formation of radial runout oscillations is impossible without a detailed analysis of previous events.
The main sources of vibration after repair and restoration measures are:
- Common cause this is the dirty or rusted face of the disc.
- It can also be caused by a "thin spot" on the rotor.
- Rough rotors.
wheel bearing;
final elements of the front circuit of the brake system;
On the other side, disc brakes have a rotor that is connected to the wheel. Brake pads attached to the calipers grip the rotor when the brake pedal is depressed, causing friction that stops the wheel. Brake pads and shoes will wear out over time and will require maintenance and replacement to ensure a safe braking system. New brake pads are 8, 10 or 12 mm thick and should be replaced if worn up to 3 mm. Rotors and calipers also need to be replaced periodically.
Common reasons for this
Rotor Outlet: This means that the rotors are moving from side to side for more than the maximum allowed amount, which is usually 0.05mm. If the rotors have recently been serviced or new ones have been installed, improper tightening can cause the steering wheel to shake when the brakes are applied. Rotors must be tightened to a specific tightening pattern and torque specifications. If not done correctly, it can damage the rotors. Worn Rotors: The rotor will deform if subjected to extreme stress for an extended period of time. It can be caused by mountain driving, towing, or even cold water hitting the hot rotor. Worn rotors lead to vibrations that vibrate or shake.
Video - Why does the steering wheel vibrate on Autotema TV
The biggest nuisance that can arise in brake system vehicle is vibration when braking. Because of this, in an extreme situation, the car may simply not stop at the right moment, and an accident will occur. Professionals attribute this to the fact that in emergency situation the driver will be frightened by the beating in the steering wheel and pedals and will weaken the pressure on the brake. Worse than these problems can only be completely inoperative. There are several main reasons for this behavior of the car - the identified problems should be eliminated immediately. Road safety depends on it.
How important is this service?
Any problem with the braking system should be dealt with immediately. Brakes that continually vibrate or shake can affect other brake components, which can increase repair costs. Plus, driving with faulty rotors is simply not safe.
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How can vibrations be detected?
Both the brake pedal and the steering wheel often knock - it is as if the anti-lock braking system intervened in the stopping process. Vibrations during braking can be detected on a dry and level surface. It is best to test the machine for vibrations on the pavement. Then ABS, if it is in the car, will not interfere with the process. It is necessary to accelerate to 80 km / h, and then abruptly, but without locking the wheels, begin to decrease the speed. If there is a characteristic vibration during braking, then you should think about repairing.
How to solve the problem with the appearance of vibration in the steering wheel?
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Causes of vibration on the brake pedal
This unpleasant phenomenon can occur for several reasons. Most of the time, the pros will celebrate the drums. Less often (but also should not be excluded) air is detected in the lines of the brake system. Sometimes the reason is badly worn tires, wheels with imbalanced balance. Curved wheels are also the vibration of the steering wheel when braking. Work problems rarely occur anti-lock braking system however, this malfunction is easily diagnosed by the vehicle ECU. Worn components will not be considered among the reasons.
Brake pad corrosion
The car is made of metal, but metal is corrosive. Even if the car is stored in a warm garage, you do not need to think that it does not rust. If the car has been parked for a long time, then corrosion appears in the places where the pads come into contact with the discs. In this case, at the first attempts to make braking, the vibration of the pedal is clearly felt. Sometimes this effect goes away by itself. But more often than not, the disc and pads have to be changed.
Poor quality pads
In addition to corrosion, they can simply be of poor quality. Getting married today is easy. And if the disks were not very good condition, then the working layer on the last will wear out unevenly. On some pads, the friction lining is crumbled in whole pieces. Vibration on the steering wheel during braking occurs as a result of a loose padding to the disc.
Changing the geometry of the brake disc
This is another reason that causes vibrations in the brake pedal and steering wheel. It consists in a sharp cooling of the disk. When the driver has an aggressive driving style and dynamically moves from one traffic light to another, then the discs simply do not have time to cool down. But overheating can also occur during quiet driving due to the caliper, which cannot provide enough clearance between the pads and the disc. 
If the car drives into a puddle, the brake disc cools down sharply and bursts or deforms. After such deformations, it looks like a bicycle wheel with a figure eight. The problem is that visually these deviations on the disk may not be visible. If the latter is of poor quality, then overheating has a very detrimental effect on it. Deformations are provided to him, which means that pedal vibration during braking is simply inevitable.
Drum brake deformations
Drum brakes are practically not subject to deformation, but sometimes they can get into trouble. They, like disc ones, can overheat (but to a much lesser extent). Overheating occurs if, in a rush, the driver forgets to release the handbrake and travels such a long distance. The driver may not even notice that the car hardly drives. When stopping, the handbrake remains raised, or hand brake twitches again. 
It is known from the school physics course that when heated, the metal tends to expand. When cooled, it narrows. In the case of a drum brake, the pads will prevent the drum from returning to its normal state. As a result, the geometry changes and takes the shape of an ellipse. Hence the vibration of the pedal To ensure safety, the vehicle's braking system has two parallel or diagonal circuits. Drum brakes can only be found on the rear axle today. budget cars... However, if in a particular auto engineers created a parallel path, then the beats on the pedal would be felt. If it is diagonal, then the vibration of the steering wheel appears here when braking. A deformed or damaged drum can be identified by the gloss of the working area. It will be patchy.
Brake cylinders
The rear and front cylinders may not work properly. Often these components of the braking system simply sour and then fail. This causes the pedal to vibrate when braking. It is very simple to solve this problem - just sprinkle WD-40 or a similar lubricant into these mechanisms (analogue is produced by "Mannol"). But more often only replacement helps.
Hub as a cause of vibration during braking
This is a very rare reason, but it should not be ruled out either. Often times, the hub is deformed only in an accident or in extremely strong impacts. However, if it falls into a hole, a wheel will more likely come off the car, or vibration will occur on the steering wheel just when driving. It will not be superfluous to check wheel bearing... If wear is observed, then it is the main reason for the appearance of beats. For diagnostics, jack up the car (hang out the wheel) and check the backlash - shake it from side to side. Backlash should be minimal, and rotation should be without sounds and hum.
Serviceable braking system and pedal beating
If the braking system is completely functional, and vibration during braking is still felt and at the same time it is not possible to detect defective elements in any way, then the problems are hidden in less obvious places. 
In such situations, experts advise you to check the wheel balancing. The fact is that when unbalanced, a centrifugal force acts on the wheel. She is the cause of all problems. Experienced driver easily identifies an unbalanced wheel. But in this case, the vibrations will be not only on the pedals, but also throughout the body. You should also check the front suspension. Vibrations in the brake pedal during braking can be a sign of deformed suspension arms or loose mountings.
It is recommended to carefully check the reliability of the fastening of the body, suspension and braking system. Workshop technicians often find loose bolts all over the vehicle. This problem will be especially relevant if the car is often operated on poor quality roads.
Stopping support
Another uncommon reason for vibration during braking is uneven caliper force. As a result, it gets jammed. But it is very difficult to identify this problem on your own - you need to visit a specialized service station.
Vibration when braking at speed
When the car drives on high speed, parts of the brake system are subject to heat. It is possible that the disc and caliper get very hot, jam and, as a result, at speed during braking - vibration or even strong shaking.
Dangerous Runout: Loose Wheels
This is an easily fixable problem. Diagnosing it is also easy. It is for this reason that various vibrations and beats often occur. Perhaps one or even all four wheels are loose. 
However simple this reason may be, it is very dangerous. If the problem is not detected in time, the consequences can be very dire not only for the driver or his passengers, but also for the rest of the traffic participants. Repair in this case, namely, if you do not notice the beats on time, can be very expensive. Hubs are broken, wheel disc deformations, brake disc deformation and broken mounting holes on the disc occur. If at braking is on vibration, it is best to double-check that all bolts are tightened securely enough. But you should not drag it to a characteristic squeak either.
What else is causing the beats and vibrations?
These reasons are rare, but still need to be considered. Sometimes there are minor faults in the steering rack, or the ball joints of the chassis of the car are too worn out. 
Also, vibration and beating will occur due to worn shock absorbers. But in this case, the effect will be felt at the moment of turning. Also, beating in the brake system and steering wheel can be triggered by strong impacts from the car.
Can the problem be ignored?
If vibration occurs during braking (VAZ-2170 is no exception), then it is better to visit the service station without delay. But you can turn a blind eye to this problem for a while - some people drive this way throughout the year. However, if the reason lies in the weak tightening of the wheel nuts, then this is very dangerous. Such beating in the braking system also places significant stress on other parts in the chassis. 
In addition, vibrations at speed, as already noted, can provoke an accident - it is very easy to lose control of the car. Driving is dangerous in itself, and if these symptoms appear, it is best to find and eliminate the cause. You should not endanger yourself and your passengers. Keep your cars in good condition - take care of yourself and your loved ones.
