What is the cause of the abnormal noise in the chassis of the car?

Generally, the abnormal noise of the automobile chassis may be: 1. The abnormal noise emitted when the vehicle starts is generally a fault of the suspension system, which may be caused by loose or damaged engine mounts; 2. The abnormal noise emitted by the vehicle when steering may be the fault of the steering system and the suspension system, because the vehicle is in the process of steering, the tilt of the vehicle makes the suspension system deformed; 3. The abnormal noise emitted by the vehicle when driving in good road conditions may be caused by the failure of the braking system components, that is, the braking system components are loose, worn, the brake drum is out of circle or the brake disc plane is uneven; 4. If there is a problem with the bearing between the vehicle connection and static, if it is a bearing problem, the driver can distinguish it with a little brake, if the vehicle does a uniform motion with a brake sound, it is a problem with the bearing; 5. Most of the abnormal noises that occur when the vehicle is driving in bad road conditions are the problems of the suspension system, or they may be caused by the loosening of the braking system; 6. Most of the abnormal noises emitted by the vehicle when accelerating, accelerating or parking are caused by the suspension system and braking system. The suspension system is mostly a grinding sound.

To reduce these abnormal noises, you need to pay attention not to drive roughly, try to avoid bumps, when encountering bad road conditions, you need to slow down, avoid wading, you can go to the repair shop to check, safety first.

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.

If there is no abnormal sound in the clutch engagement, but there is an abnormal sound after pressing the clutch pedal, it may be that the front bearing of the first axle is damaged. The reason is that when the clutch is engaged, the first shaft rotates with the flywheel, and the front bearing of the first shaft has no relative movement, so there is no abnormal sound or abnormal noise; When the clutch is disengaged, the first shaft is separated from the flywheel, and the inner and outer rings of the front bearing of the first shaft are opposite.

The rubber bushing on the chassis is aging, and the abnormal sound of the chassis of the car is due to the aging of the rubber bushing on the chassis.

Just overhaul the car, it's a hidden danger, and I'm really helping you look forward to adopting

Check the drive shaft and universal joint for deformation or oil leakage. If there is deformation of the transmission shaft and universal joint, it needs to be replaced in time, if it is only a lack of oil, it needs to be relubricated, and if necessary, the oil seal should be replaced, check whether the brake caliper and brake disc bracket are loose, and check whether the brake pads are abnormally worn.

1. Possible reasons for interference between parts: due to collision or installation of other equipment, the two parts affect each other.

2. Possible causes of bolt or nut looseness: a. Driving on a road with poor road conditions for a long time, the bolt is 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. Possible causes of transmission shaft universal joint failure: the dust cover is broken or the oil leakage is not repaired in time.

Solution: Replace the new transmission shaft universal joint.

4. The abnormal noise caused by the damage of the ball joint, suspension and connection bracket may be caused: after long-term use, the ball head is loose or the rubber liner is aging and cracked.

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

5. Possible causes of abnormal noise of braking system: 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.

When the clutch release bearing is damaged, the clutch plate cannot be completely disengaged, which eventually leads to an abnormal sound during acceleration.

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.

The possible causes of abnormal noise in the automobile chassis are as follows:

1. The abnormal noise emitted by the vehicle when starting is generally a suspension system failure, and it may also be caused by loose or damaged engine mounts.

2. The abnormal noise emitted by the vehicle when steering may be the fault of the steering system and suspension system. As the vehicle is steering, the tilt of the vehicle deforms the suspension system and also participates in the movement.

3. The abnormal noise emitted by the vehicle when the road conditions are good may be the fault of the braking system components. Caused by loose or worn brake system components, loss of roundness of the brake drum or uneven plane of the brake disc.

4. There is a problem with the bearing between the dynamic and static connection of the vehicle. If it is a bearing problem, the driver can distinguish it with a little brake; If the brake sound does not change when the vehicle moves at a constant speed, it is a problem with the bearing.

5. The abnormal noise of the vehicle when driving in bad road conditions is mostly caused by the suspension system, or it may be caused by the loosening of the braking system.