Suddenly appearing grazing The car is a signal that cannot be ignored. The sound of metal against metal not only irritates the driver’s and passengers’ hearing, but also indicates critical wear of the nodes or their complete destruction. Ignoring such an acoustic anomaly often results in costly repairs and, more importantly, poses a direct safety risk on the road.
The driver must learn to distinguish between the nature of the sound, as the accuracy of the initial diagnosis depends on it. A deaf hum may indicate bearings, while a voiceful, piercing grind is most often associated with the braking system or suspension elements. Understanding the nature of noise allows you to quickly localize the problem and make the right decision about further actions.
In this article, we will discuss in detail the main sources of extraneous sounds, methods for their detection and algorithms for troubleshooting. You'll find out why. brake-pad They can make sounds even when they are in good condition and how to determine if it’s time to change. SRUSS Or hub bearings.
Diagnosis of the brake system: pads, discs and calipers
The most common cause of fearful grinding is precisely brake. If you hear a metal clang when pressing the brake pedal or even when rolling freely, the first thing to do is check the residual thickness of the friction linings. When the working surface is completely erased, the metal base of the pad begins to contact the brake disc, causing deep furrows and a characteristic sound.
However, grinding does not always mean a critical breakdown. Sometimes the cause is the hit of a small stone or sand between the disk and the brake-board. In this case, the sound may appear abruptly and just as suddenly disappear after several cycles of braking. It is also worth checking the condition of the guide calipers: if they are acidified, the pads may not be fully decompressed, causing constant friction and heating.
⚠️ Warning: Operation of a car with fully erased brake decks leads to rapid destruction of the brake disc. Replacing the pair "disk-pad" will cost 3-4 times more expensive than timely replacement of consumables.
For accurate diagnosis, it is necessary to visually inspect the caliper through the wheel disc or dismantle the wheel. Pay attention to the color of the disk: if one of them is darker than the others (has a bluish or black hue from overheating), then it is in this node that constant friction occurs. Also check availability metal-spin on the inside of the wheel is a sure sign of active destruction of friction materials.
☑️ Brake diagnostics
Malfunctions of suspension and chassis
If the grinding is heard not only during braking, but also when passing irregularities or corners, the search zone shifts to the side. running-piece. Worn ball supports, Silentblocks or stabilizer bushings can make various sounds, but it is the metal grind that often indicates the absence of lubrication in the hinge joints or their complete wear.
Special attention deserves bearing-bearing shock absorber racks. When they are destroyed when turning the steering wheel, not only a crunch can occur, but also a grin, giving to the body. Owners of independent suspension cars often face the problem of wear of the upper supports, which requires immediate replacement in order to avoid rig breakaway.
Diagnosis of the suspension is better carried out on the lift or observation pit, using the mounting blade to check the backlashes. Swinging the levers and tractions, you can hear the characteristic clicks or see the movement of parts where it should not be. It is important to check the condition of the anthers: if they are torn, the lubricant is washed out, and the rubbing parts begin to work "dry".
Problems with SRUS and transmission
Hinges of equal angular velocities (SRUS) - critical elements of the drive of front-wheel drive and all-wheel drive cars. The internal and external grenades transmit torque from the gearbox to the wheels. When the separator is destroyed or an abrasive enters the hinge (through a torn anther), intense wear of metal components begins.
Most often, a faulty SRUS emits a characteristic crunch when the wheels are turned and the beginning of movement. However, in the later stages of destruction, the sound is transformed into a constant metallic grinding or hum, which is amplified when speed is set. If you ignore this symptom, the hinge may simply jam or fall apart on the go, leading to loss of control.
Checking the state of the actuators is carried out visually (the presence of lubrication around the wheel) and by ear. Sharp acceleration with the steering wheel turned out to be the best test for external SRUS. To check the internal hinges, it is often necessary to drive the car onto the lift and sway the drive in the axial direction, checking for backlash.
| Type of malfunction | Nature of sound | Conditions of occurrence | The risk of neglect |
|---|---|---|---|
| Wear of brake pads | The squeak that turns into a squeak | When you apply the brake | Disc failure, brake failure |
| The destruction of SRUS | Crunch, then hum and gnash | Turn, break, break. | Drive jamming, road accident |
| Stack bearing | The hum turning into a howl | Constantly changing at speed. | Wheel tear, jamming |
| Protective shield | Calling metal clang | Constantly or when braking | Damage to the brake disc |
When identifying problems with the transmission, it should be remembered that replacing one SRUS often entails replacing the anther and lubricant, and sometimes the entire drive assembly. The use of low-quality analogues leads to a repetition of the problem after 5-10 thousand kilometers.
Stage bearings: the quiet enemy
Although a classic symptom of malfunction hub bearing It is considered a hum or howl, at certain stages of destruction it can make grinding sounds. This occurs when the bearing separator crumbled and the balls began to move chaotically between the clips, breaking them.
Diagnosing a faulty bearing can be done in several ways. The simplest method is to disperse the car and listen to how the sound changes during the rearrangement. When the body is distorted, the load on the bearings changes: if the sound is amplified when turning to the left, then the problem is in the right bearing, and vice versa. You can also lift the car with a jack and sway the wheel in horizontal and vertical planes.
⚠️ Warning: If the hub bearing warms up strongly after the trip (check carefully without touching your hands immediately after stopping!), this is a sign of critical wear or improper tightening of the hub nut. Overheating can lead to jamming of the wheel at high speed.
Modern cars are often equipped with hub assemblies in the assembly, where the bearing is inseparable from the hub. In such cases, the replacement is made only by the entire node. It is important to observe the tightening moment and use a dynamometer key when installing, since the pulling will kill a new bearing in a matter of kilometers.
Foreign objects and protective elements
Sometimes the reason is banal and lies in the hit of a foreign object in the moving parts of the car. A stone stuck between the disk and brake-boardHe is capable of making a deafening grin. Also, the source of sound can be the detached heat shields of the muffler, which begin to vibrate and rub against the body or elements of the exhaust system.
A common cause is plastic slats (lockers). If the mounts are weakened or fell off, the edge of the underwing can fall into the rotation zone of the wheel or brake disc. Plastic melts and wears off quickly, producing an unpleasant smell and friction sound.
To eliminate such problems, it is enough to conduct a visual inspection of the wheel arches and the space under the car. Check whether the elements of the exhaust system hang out, whether the anthers are intact and whether plastic protections are securely fixed. Sometimes it is enough to simply bend the brake shield with a screwdriver to eliminate contact with the disc.
Remediation and prevention
Elimination of the grinding depends directly on the identified cause. If the brakes are the problem, the pads are replaced and, if necessary, the discs are drained or replaced.
In case of problems with suspension or shruses, worn-out nodes are replaced. After replacing the suspension elements (levers, rods, tips), it is necessary to check and adjust the angles of the wheel installation (fall-off). Ignoring this stage will lead to accelerated wear of new rubber and unstable behavior of the car on the road.
As a preventive measure, wash your car regularly, paying attention to the wheel arches to notice ripped anthers or leaks of technical fluids in time. Diagnose the chassis every 10,000 to 15,000 kilometers, especially if you are often driving on roads with poor surface.
Why would the car be fastened when the brakes are new?
If the brake pads and discs have been replaced recently, the cause of the grinding may be the process of grinding new parts. In the first 100-200 km of run, a slight noise is possible. However, if the grinding is strong, it may have been installed low-quality pads with metal inclusions, or when mounting between the pad and the disc, debris got. It is also worth checking the condition of the guide calipers.
Is it dangerous to drive if there is a metallic grinding?
Driving with that sound is extremely dangerous. Grinding means contact of metal with metal, which leads to rapid destruction of knots. In the case of brakes, this threatens to fail the braking system. In case of problems with suspension or drive, the wheel may be removed or the mechanism jammed at speed, which can lead to a severe accident.
How to distinguish the sound of a shruce from the sound of a bearing?
The SRUS usually crunches or snaps at a sharp start with the wheels turned out. The bearing of the hub emits a monotonous hum or howl, which changes in tonality depending on the speed of movement and is enhanced when cornering (loading on the side). The scroll often indicates the critical stage of destruction of both nodes.