What are the abnormal sounds of the chassis? How to solve?

The main causes of abnormal sounds of chassis

The abnormal noise caused by the deformation, break or wear of the parts: increased the gap:

This abnormal noise is mainly due to impact or overload to deform or break the parts; due to wear, the gap between the components increases and loosen the abnormal noise. In this case, through plastic surgery or replacement parts, the abnormal sound can be eliminated by restoring the normal cooperation of parts.


Bolt, rivet, welding loose abnormal noise:

This situation is more likely to appear on cars with a long age and poor maintenance, and generally more obvious when starting or braking. It can be solved by fastening or replacing bolts, nuts (especially disposable nuts). Such phenomena will also appear on the new car. For example, ordinary Santana and Santana 3000 cars have a “click” sound when turning, mostly caused by the fixed nuts of the front shock absorber. There was a gap, and the inner wall of the suspension sleeve collisted with a sound.

The abnormal noise caused by the transmission shaft universal section:

If there is a failure of the transmission axis universal section, the vehicle will make a sharp sound during driving, especially when accelerating and turning. It is generally caused by the excessive gap between the universal section or the card issuance. Most of the situations are caused by the rupture of the dust cover.

The abnormal noise of connecting the ball head and the rubber bracket:

The abnormal sounds caused by the suspension and the looseness of each connector and the rubber brackets, such as the rod head, connecting ball head, bracket head, gearbox bracket, and shock absorber, etc. This abnormal noise is very obvious on the uneven road surface. Whether it is acceleration, braking or steering. As long as the road surface is uneven, the abnormal noise will appear, and it is continuous. If the gap becomes larger between the ball head and the ball head seat, as the body continues to bump continuously, a continuous impact will occur between the two, so there is abnormal noise. If it is severe, there will be abnormal noise when starting or braking, and this situation can only be replaced.

The abnormal noise caused by the loosening of the brake system parts:

The abnormal noise caused by the loosening of the brake system components, including the loosening of the brake, brake pliers, and brackets, will cause abnormal noise. This situation generally occurs during braking. The braking delay will cause the braking abnormal noise during driving, because the total pump oil recovery of the hydraulic brake is blocked, the exhaust valve stagnation or adjustment of the exhaust valve of the gas pressure brake; Cause.

Due to the abnormal noise caused by the abnormality of the wheel bearings or tires:


This situation occurs when it reaches a certain speed. It is the sound of “hum, hum”, and the abnormal noise increases with the increase of the vehicle speed. Most of them are caused by the ablation of the wheel bearing or tire wear. It is simple and effective to judge the good or bad of the hub bearing. One hand is placed on the shock absorber or spring, and the other hand rotates the tire. If the shock absorber or spring has obvious vibration, it means that the bearings have been damaged. If you do n’t feel vibration, it indicates that there is no problem with the bearings, then the abnormal noise should be caused by abnormal wear of the tire.

Case 2 cases of chassis abnormal noise

Case 1: Sagitar cars are abnormal when there is an abnormal noise in the front of the car when driving

A Sagitar car has a mileage of about 122,000 kilometers. According to the customer, after the vehicle is driving for a distance, the front and lower part of the vehicle emit a rhythmic “bombardment, bombardment” sound. The faster the vehicle speed, the faster the frequency of the abnormal noise. The position of the occupant in the front of the car is obviously vibrating.

Diagnosis and exclusion:

① First test the car on the road. When the abnormal noise appears, remove the transmission gear first, then step on and lift the clutch pedal. The abnormal noise does not change, indicating that the failure is not in the clutch and the transmission.

② The maintenance technician drove the car back to the repair plant and raised the vehicle with a raising device to allow the vehicle to run at low speed without load without abnormal noise.

③ Check the two front axles with abnormal noise, no noise. The front and rear wheel tires of the vehicle still exist on the post -road trial.

④ Raise the vehicle again. The maintenance technician touched the left and right transmission shafts with his hands, and found that the ball cage in the right transmission shaft was severely heated.

⑤ Remove the right transmission shaft, remove the inner ball cage anti -dust cover, and find that the lubricating oil inside has dried up. Essence

⑥ After replacing the new right internal cage, the test drive runs, the abnormal noise disappears, and the fault is completely excluded.

Case 2: POLO sedan during driving, an abnormal noise is made, and the abnormal noise changes with the speed of the car and the pavement


A POLO sedan has a mileage of about 71000km. The customer introduced that during the driving of the vehicle, the front suspension made abnormal noise, and the abnormal noise changed with the speed of the vehicle and the road conditions.

① First raise the car raised by the car, then use a large screw rotation or pry rod to check whether each connection ball sales and bolt are loose. As a result, there is no such situation.

② View the shock absorber, exudate without hydraulic oil, and the vibrator tube is not hot. It is initially determined that the tire tire wear is inspected.

③ Check the left and right spiral springs, no deformation and cracks, and the length of the left and right compression is not much different (this can be judged from the situation where the front of the body is not skewed).


④ On the raising rack, no suspension part was found to be caused by loosening and damage. Therefore, the maintenance technician decided to park the car on the flat ground and swing the front of the body to make it a large amount of up and down vibration. I heard that the left shock absorber spring had “click, click” abnormal noise, so that the abnormal noise was diagnosed from the left spiral spring.

⑤ Use a dedicated tool to disassemble the left vibrator sprint spring to check the length of the spiral spring free length of 340mm (the standard length is 339mm). Customers introduced that this is the new spring that replaced it. The maintenance technician estimates that the elasticity will not be attenuated, but in the inspection, it is found that the sliding pillar thrust bearing is damaged and disintegrated. The abnormal noise failure is mainly due to the repeated extension and compression of the shock absorber spiral spring after the bearing disintegration. Failure to be checked and replaced in time.

⑥ The maintenance technician replaced the shock -absorber sliding pillar thrust bearing. After testing, the fault was completely excluded.

Maintenance prompt:

When installing the shock absorber spring, you should pay attention to replace the new piston nut. This piston nut can be used at one time, and it must be replaced once it was disassembled.

Diagnosis and exclusion:

Author: ArticleManager