The appearance of an extraneous hum in the front of the car is one of those alarming symptoms that cannot be ignored. monotonnyj low-frequency sound, which increases with increasing speed, often indicates serious mechanical problems in the chassis units. Unlike squeaking or thumping, which can be periodic, a constant hum indicates continuous friction or vibration of parts.
Many drivers mistakenly believe that if the car is driving and the steering wheel is not shaking, then you can postpone a visit to the service. However, front-wheeler It is often a precursor to jamming the hub or breaking the bearing, which at high speed can lead to an emergency. Understanding the nature of sound helps not only save budget, but also save lives.
In this article, we will discuss in detail the main causes of noise, methods of self-diagnosis and nuances of repair of various elements of the front suspension. You will learn to distinguish the sound of worn-out SRUS from the hum of the bearing and understand when to pull with repair is simply dangerous.
Diagnosis of a hub bearing: the main source of hum
The most common cause of a monotonous hum, which increases in proportion to the speed of the car, is failure. hub-bearing. In the initial stages of wear, the sound may be barely distinguishable, resembling a hum from a road surface, but over time it becomes intrusive and loud. A characteristic feature is that when you turn the steering wheel in one direction, the load on the bearing changes, which affects the volume of sound.
To determine exactly which side of the problem is coming from, you can perform a simple diagnosis on the go. When driving at a safe speed, try to waddle slightly from side to side. If the hum is amplified when turning to the left, then the problem is most likely in the right wheel, since it accounts for the main load. And conversely, when rolling to the right, the left bearing makes noise.
Ignoring the symptoms leads to overheating of the node, washing out the lubricant and eventual jamming of the wheel. In modern cars with ABS, bearing wear is often accompanied by a tanning of the corresponding lamp on the dashboard, since the gap between the sensor comb and the sensor itself is broken.
β οΈ Attention: If the hum is accompanied by vibration on the steering wheel or heating of the wheel disc after the trip (check with your hand without touching the brake pads), the operation of the car is prohibited. The risk of wheel detachment or complete destruction of the hub is extremely high.
SRUS and drives: how to distinguish crunch from hum
hinges of equal angular velocities (Ε RUS) are most commonly associated with the characteristic crunch when the wheels are turned, but in the early stages of wear they can also emit a low-frequency hum. The internal grenade (tripoid) when backing begins to vibrate, transmitting unpleasant sensations to the body and creating background noise, which is easily confused with the bearing.
Diagnosis of external SRUS is simple: turn the steering wheel to the point and move. Crunch means the death of the outer hinge. With internal more difficult - they buzz when accelerating under load. To check them, find a viewing pit and swing the drive with your hand. The presence of a tangible backlash in the hinge indicates the need for replacement.
- π οΈ External SRUS: Crunchy in turns, hums rarely, only with severe destruction.
- π οΈ Internal SRUS: Gives vibration and hum during acceleration, especially noticeable at high speeds.
- π οΈ Wheat: Even if there is no noise, a torn anther means the imminent death of the hinge due to the ingestion of abrasive.
Often drivers change the bearing, and the drive buzzes. To avoid unnecessary expenses, always conduct a comprehensive check. In some cases, the hum may not be issued by the hinge itself, but skewed or poor-quality. driveshaftwhich, when rotating, touches the elements of the subframe.
Can I drive with a crispy SRUS?
You can drive, but not for long. The hinge can fall apart at any moment, leaving you without a wheel drive. On front-wheel drive, this often results in the semi-axle flying out of the gearbox, oil leaking out and movement becoming impossible.
Brake system: hidden sources of noise
Brake mechanisms rarely buzz constantly, but there are exceptions. If brake-pad completely erased, the metal base begins to rub against the disk, creating a piercing squeal or low hum. However, a more insidious problem is the wedging of the caliper or guides.
When the caliper does not diverge completely after braking, the pads remain pressed against the disc. This causes constant contact, heating and a characteristic hum of friction. Check this out after the trip: carefully touch the center of the wheel disc (not the brake disc!). If one wheel is much hotter than the others, then the caliper is squirrel.
Another reason may be the deformation of the brake disc. The "eight" on the disk causes the beating of the pads, which at certain speeds resonates and is perceived as a hum. Measure the beat can be indicator clock type, fixing it on the fixed part of the suspension.
When replacing brake discs, always check the condition of the hub. If there is rust or soot on the landing plane, the new disc will get curved and begin to hum and beat after 1000 km of run. Clean the plane with a brush to metal.
Rubber and discs: when the cause is outside
Before climbing under the car and unscrew the nuts, it is worth eliminating the most banal option - tire. "Blow" can rubber with worn or uneven tread (the so-called "hernia" or spotted wear). Also, the source of noise are wheels with disturbed geometry.
After falling into a deep hole, the disc can get a bend barely noticeable to the eye. At low speeds, this is not felt, but on the track the beat creates a constant low-frequency background. Balancing weights, if they are many or unstuck and hanging inside the disk, can also create a strange ringing or hum.
| Type of malfunction | Nature of sound | Dependence on speed | Dependence on the road |
|---|---|---|---|
| hub bearing | Monotonous hum, howling | Direct (the faster, the louder) | It doesn't matter. |
| SRUS (internal) | Vibration, humming | Noticeable when accelerating. | It doesn't matter. |
| Rubber (wear and tear) | Noise like a plane hum | Nonlinear. | It depends heavily on the coverage |
| Brake (wedge) | Whistling, gnashing, humming | Constant or pressed | It doesn't matter. |
Particular attention should be paid to the pressure in the tires. Over-pumped or under-pumped rubber changes the contact spot, which can lead to a change in acoustic comfort and the appearance of a hum, which drivers often mistake for suspension failure.
Other elements of suspension and transmission
If the bearings and sroes are all right, you should pay attention to the bearing-bearing shock absorber racks. When they are destroyed, the rack can make sounds when rotating, but more often it is still a crunch or a knock. However, in combination with other factors, the overall background changes.
In cars with all-wheel drive source hum ahead can be a transfer case or front gearbox. Wear gears or lack of oil in these nodes causes howling, very similar to a hub. You can distinguish by the fact that the hum of the transmission often changes when the gas is discharged, and the hub depends only on the speed of rotation of the wheel.
βοΈ Primary diagnosis of hum
Also, do not forget about the protection of the engine crankcase. If it is deformed after hitting the curb, it can vibrate against the body or elements of the exhaust system, creating a resonating hum that is amplified at certain engine speeds.
β οΈ Attention: Never lubricate bearings in the hope of removing the hum. If the bearing buzzed, it has already gone the processes of destruction (pitting, metal painting). Lubrication will only temporarily reduce the noise, but the knot will still jam at the most inopportune moment.
Elimination methods and repair costs
Repair of the front suspension when a hum appears most often involves replacing faulty nodes. Stage bearings In modern cars often change in the assembly with a hub. It is more expensive, but more reliable and faster, as it does not require the use of a hydraulic press to press the old bearing.
Replacing SRUS is also a standard procedure. It is important to buy kits with new anthers and lubricant. Using old clamps or not enough lubrication will result in re-repairs in a short time. When replacing the drives, it is recommended to immediately check the condition of the PPC glands.
The cost of work varies depending on the brand of the car. On budget models, the replacement of the bearing can take 1-2 hours, while on premium cars with complex multi-link suspension, the repair time increases. Do not skimp on spare parts: cheap Chinese counterparts are 3-4 times less than the originals or quality substitutes.
The main rule: if the front wheel buzzes, delaying repairs increases the total amount of the check. A broken bearing can damage the seat in the swivel fist, which will require replacing the entire rack or fist entirely.
After any intervention in the geometry of the front suspension (replacement of levers, Silentblocks, steering tips), it is necessary to do fall-up. Otherwise, the car will βeatβ rubber, and the hum of uneven tire wear will return very soon.
Can a new wheel hum after tire mounting?
Yes, if the master screwed the wheel badly, did not remove the old balancing loaders or damaged the disk during installation. Also, the cause may be the marriage of the tire itself (shifting the layers of the cord), which manifests itself in the form of a hum and a beat.
It only goes cold or only hot β what does that mean?
If the hum appears only on a warmed-up car, this may indicate thickened lubrication in the knots (rarely) or, conversely, the thinning of oil in the gearbox. Most often, temperature dependence indicates thermal expansion of parts and a change in gaps in the brake system.
Why does it hum after replacing brake pads?
The new shoes should be worn. If it hums strongly, it is possible that the pads do not fit in thickness or material, or were installed without lubrication on the guides. It could also have been a pebble between the disc and the protective casing.
Is it dangerous to drive with a hum in wheels 100 km to service?
If the hum is quiet and does not increase sharply - you can reach it, observing the speed limit. If the sound is growing, accompanied by vibration or heating, call a tow truck. The risk of being left without a wheel on the track is not worth saving on evacuation.
Could the engine be causing the hum?
The engine rarely gives a hum in the wheels. However, the vibration of the motor through the cushions can be transmitted to the body and resonate with the floor. Usually, the hum of the engine changes from the revs (gas), and not from the speed of the car.