What should I do if there is an abnormal noise in the chassis of the car?

On the issue of abnormal noise of automobiles, it is difficult for ordinary car owners to distinguish which ones are abnormal noises and which ones are reasonable abnormal noises. Only nearly 20% of the vehicles that went to the repair shop to detect abnormal noises really had problems. In the case of a turbocharged engine, there is a must be a difference between the sound and the sound of a naturally aspirated engine; Models with engine guards may also make noises due to friction; After some car owners come into contact with different cars, it is likely that they lack their own understanding of mechanical knowledge, so they can distinguish the abnormal noise of the car and avoid wasting time and energy.

Second, the identification method of car noise:

In practice, due to the limitations of working conditions, it is difficult to measure the sound of the car with special instruments, and the sound of the car can only be described and compared with the judgment of the sound in daily life. For example, the "rattle" sound caused by the dry friction of the bearing, and the "click" sound similar to the small hammer hitting the cement floor caused by the excessive valve clearance.

1. Correctly distinguish between normal and abnormal sounds.

The vibration of each mechanism in the work of the car will emit a variety of sounds, but the sound does not mean that the car is faulty, in order to avoid unnecessary disassembly, we must first distinguish between normal sound and abnormal noise. The normal vibration sound of each system component (such as the noise on the surface of the engine), the impact sound of the gear when shifting, the air intake sound and exhaust sound of using gas as the working source, and the gear meshing noise are all normal sounds. Abnormal noise (abnormal noise) can be divided into slight noise, general noise and malignant noise according to the impact on the performance of the car.

Slight noise, such as the flashover sound of high-voltage electric leakage, the slight loose sound of rolling bearings, etc., the general volume is small, the degree of wear of the parts is not large, and there is no significant change for a long time, and this kind of fault can still maintain the normal operation of the car without repair.

3. When diagnosing abnormal noise, attention should be paid to creating good auscultation conditions and trying to eliminate the interference of other noises, so as not to affect the accuracy of judgment.

It is best to consciously amplify or reduce the sound, that is, use a screw or other metal rod as a stestological instrument to contact the sound part to amplify the sound, or use a single cylinder fire cut-off to reduce the sound to meet the diagnostic needs. The auscultation site should be kept quiet to minimize human interference.

Hello! Glad for your question.

Loose chassis generally occurs in older cars, when the car is driving in bad road conditions, the steering wheel will feel unstable, and there will be abnormal noises from the bottom of the car, usually the old driver can feel that the whole is a little loose, when encountering such a situation, it means that the chassis may be loose, and the reasons for this situation are divided into several types, only by understanding the reasons, can we better prevent the occurrence of this problem.

The first reason is the aging of rubber parts, we all know that the elasticity of rubber is particularly good, which can buffer the friction between parts and reduce noise at the same time. However, this kind of thing has a lifespan, and it will age after a long time, and the elasticity is not as good as before, so the buffering capacity will decrease, resulting in abnormal noise in each part, so it is necessary to check these rubber parts regularly and replace them in time.

The second possibility is the reason for the shock absorber, the main role of this part is to inhibit **, when the car is driving in the dustpan section, it will have an impact with the road surface, and the shock absorber can well ensure the smoothness of the car, if the shock absorber is damaged, there will be a scoop phenomenon, so that the chassis is loose, so usually check the shock absorber, if there is a leakage to repair in time.

The third is the clearance of the parts, that is to say, the ball head may be loose, this part is like the joints of the human body, if the ball head is loose, there will be a large gap between the lever and other connected parts, if the gap is too large, when crossing some dustpan roads, the screws between the subframe and the suspension will be loose, then the chassis will become loose and sluggish, so usually check these two parts. Thank you.

No matter what "abnormal noise" there is, it is the premise to find the problem and repair it in time without delay. According to the results of the rough inspection, the relevant faulty parts or the personnel reasons of missing installation, reverse installation, and unfastening, timely treatment, noisy and repaired rock collision, fixation, etc. Eliminate potential safety hazards.

There is a problem with the brake pads. The phenomenon is: there is an abnormal sound under the front wheels, especially when the steering wheel is played.

Judging method: When it sounds, step on the brakes and see if the sail still rings. If it doesn't go off, you can basically laugh and hail to determine that there is a problem with the brake pads (there is also a possibility that there is a problem with the outward lifting cage).

Solution: Replace the brake pads.

1. Distinguish between engine squeak and rear axle squeak.

First of all, the car is driven on the flat road for a certain mileage, so that the working temperature of the rear axle rises to normal, and then when the car makes an abnormal noise, write down the speed, after stopping, put the transmission in the neutral position, and then slowly accelerate until the speed of the engine is equivalent to the speed when the abnormal noise occurs, observe whether there is any abnormal noise, and can be repeated several times to determine whether the abnormal noise is caused by the abnormal condition of the exhaust or the engine.

2. Distinguish between tire noise and rear axle noise.

Tyre noise varies with the road surface, but not rear axle noise. When the speed of the car is below 48kmh, the rear axle noise disappears, while the tire noise continues. The noise of the tires is the same when the car is driving and coasting, but the noise on the rear axle is different.

3. Distinguish the abnormal noise of the wheel bearing and the noise of the rear axle.

When the car is driving and coasting, the noise of the front wheel bearing remains unchanged, if the speed of the vehicle remains the same and the brake is applied slightly, the wheel bearing can reduce part of the load, so that the noise can be reduced, and the noise source can be found.

When the speed is greater than 48kmh, unless the rear axle is seriously damaged, the noise of the rear wheel bearing can rarely be heard under normal circumstances, when the car is coasting or neutral, the cracked rear wheel bearing will produce a "rumble" sound, and the corroded rear wheel bearing will make a "rustling" sound.

4. Distinguish the abnormal sound of the reducer cone active bearing and the differential bearing.

The reducer bearings usually produce a harsh "rumble" or "rattle" sound, and the sound beat is stable and changes with the speed of the vehicle.

The sound of the front bearing of the bevel driving gear of the reducer is louder when the car is coasting, and the noise of the rear bearing is louder when driving.

The noise of the differential bearing is usually a constant harsh sound, but its beat is much more tempered than that of the reducer tapered drive gear bearing.

5. Distinguish the noise of the rear axle gear.

In a normal straight line, the noise is not audible because there is almost no relative movement of the differential half-shaft gears and planetary gears.

During the driving of the car, the reason for the abnormal sound of the rear axle gear is mostly caused by poor lubrication, which leads to the reducer gear grinding scars, if the abnormal sound can be heard at various sliding speeds, it means that it is caused by the loosening of the nut of the reducer driving gear.

If there is an abnormal noise on the chassis of the car, you need to report to the maintenance department to do a detailed inspection to see if it is. Is there a loose screw or a problem with this shock spring?

There are solutions to chassis noise, such as interference between parts, which can be avoided by repairing or replacing the parts in question. Or the bolt nut is loose and the bridge is not regretted, the tightening torque is insufficient or the bolt specification is wrong. The universal joint of the propeller shaft was faulty, so a new propeller shaft universal joint was required.

If noise is generated due to damage to the individual ball joints, suspension, and connection brackets, replace them with new ball joints or support pads. There are many reasons for this problem, such as chassis noise. Among them, there is a fastening type, and the swing arm and brake make noise when passing over uneven roads.

There is also noise when the brakes are locked. There is also the place where the suspension of the engine is connected to the body, to see if there are any signs of loosening. If there is any suggestion, you can change it to a new one.

1.The sound of disc brakes: The disc brake shoes are installed on the support frame of the brake cylinder, and the backs of the two shoes are equipped with anti-noise gaskets, and the upper and lower friction plates are equipped with support plates or support springs, and the upper and lower ends are equipped with shock-absorbing spring plates or guide plates.

The above accessories enable the brake shoe to play the role of support, guidance, positioning and shock absorption. However, if a part is bent and deformed, leaks before being damaged, or falls, it will lose its proper function and produce noise. 2.

The sound of the front suspension ball joint: There are various types of front suspension used in small cars, such as longitudinal leaf springs, transverse leaf springs, torsion bar springs, or coil springs. In suspensions, a ball joint structure is often used instead of kingpins.

Most of the ball joints are closed and non-removable. There is no grease nipple on the ball head, lubrication is difficult, it has been used for a long time, or there will be noise due to the use condition, road surface condition, lack of oil wear, etc. 3.

Noise from the front wheel shock absorbers: Damage to the shock absorbers can affect the driving condition of the car. If there is damage, traces of oil leakage can be seen on the outside, and noise will be generated at the same time.

4.Propeller shaft universal joint noise: If the front drive constant velocity universal joint is faulty, the car will make noise when driving, especially when turning or accelerating suddenly, it will make a "click" sound.

That's all for you. Do you understand everything after reading it? What are the solutions to the abnormal noise of the chassis? I don't know what everyone thinks. If you want to know more, keep reading the other articles of this **!

1. Interference between parts.

Possible cause: The two parts affect each other due to impact or the installation of other equipment.

2. Loose bolts or nuts.

Possible reasons: a. Driving on the road with poor road conditions for a long time, the bolts are naturally loosened;

b. Improper disassembly and installation of bolts damage;

c. The tightening torque is not enough or the bolt specification is wrong.

Solution: Tighten or replace the bolts and nuts.

3. The universal joint of the transmission shaft is faulty.

It may be caused by a ruptured dust cover or oil leakage that is not repaired in time.

Solution: Replace the universal joint with a new transmission letter.

4. Abnormal noise caused by damage to each ball joint, suspension and connecting bracket.

Possible causes: After long-term use, the ball joint is loose or the rubber liner is aging and cracking.

Solution: Replace the ball head or support pad with a new one.

5. Abnormal noise of braking system.

Possible causes: a. Loose brake pads, brake calipers or brackets;

b. Brake pad or brake disc failure;

Solution: Check whether the braking system is loose and whether the brake pads and brake discs are abnormally worn. Sliding.

If the chassis of the car creaks, check the rubber sleeve for replacing the brake pads or balance bar. If the problem persists, you can disassemble and check the meshing clearance between the differential gear and the reducer gear, the preload of the reducer bevel drive gear bearing, and the contact traces of the reducer gear to eliminate abnormal noise.

There are many reasons for this problem, such as tightening, such as your car's lower swing arm and sleepy stove clear brakes are normal to make noise when passing through uneven roads, and it is also normal for brakes to lock up, and they will also make abnormal noises. Pay attention to the rear axle and bodywork, check the rear strut, the bumper block is not falling off, the exhaust pipe can also make abnormal noise, then interference noise, which is usually required by the design, the engine has several mounts.

Inspection method for aging and loosening of the opening glue of the balance bar: lift the car, grasp the balance bar with your hands, and shake it vigorously. Righteousness cannot be shaken under normal circumstances.

If there is a loosening of the stick, the opening glue of the balance bar needs to be replaced. (The balance bar is also called the anti-roll bar), and the ball head of the balance bar suspension is aging. It is necessary to remove the tire and observe whether the rubber at the head of the boom ball is aged and cracked.

If it is aging, it needs to be replaced directly.

In your case, the abnormal noise is indeed difficult to deal with, it is recommended to go to 4S to check, let them try more, it should be able to determine what is the problem!