As a core component of the chassis system, the automobile shock absorber directly affects the driving stability, comfort, and safety of the vehicle. Once a failure occurs, it will not only significantly reduce the driving experience but also cause chain problems such as abnormal tire wear and reduced steering accuracy, and even increase the risk of traffic accidents. Starting from the working principle of shock absorbers, this article will comprehensively list the common causes of failure, judgment methods, and professional maintenance solutions, providing car owners with a practical guide to deal with failures.

1. Core Function and Working Principle of Shock Absorbers

Automobile shock absorbers mainly achieve the shock absorption effect by suppressing the reciprocating vibration of the spring. Their core principle is to use the flow resistance of hydraulic oil in the piston cavity to convert the mechanical energy generated during vehicle driving into heat energy, which is then dissipated. Under normal working conditions, shock absorbers can effectively absorb the impact caused by road bumps, ensure that the wheels are always in contact with the ground, and maintain the stability of the vehicle body. Common types of shock absorbers include hydraulic, pneumatic, and electromagnetic ones. Among them, hydraulic shock absorbers are widely used in family cars due to their low cost and high reliability; pneumatic and electromagnetic shock absorbers are more commonly found in mid-to-high-end models and have more flexible damping adjustment capabilities. Regardless of the type, any damage to the internal structure will directly lead to the failure of the shock absorption function.

2. Four Common Causes of Shock Absorber Failure

(1) Aging or Damage of Seals​
The oil seals and O-rings inside the shock absorber are key components to prevent hydraulic oil leakage. During long-term use, affected by high temperature, oil pollution, and vibration, the seals will gradually harden and crack, resulting in hydraulic oil leakage. When the oil volume is insufficient, the piston cannot form effective damping during movement, so the shock absorption effect will be significantly weakened, and in severe cases, a "thudding" metal impact sound will occur. This type of failure is most common in vehicles with a driving mileage of more than 80,000 kilometers, especially in vehicles that often drive on bumpy roads, where the aging speed of the seals will accelerate.​

(2) Deterioration or Contamination of Hydraulic Oil​
As the transmission medium of the shock absorber, hydraulic oil needs to be clean and have an appropriate viscosity. If it is not replaced for a long time, the oil will produce impurities due to oxidation or be mixed with dust and metal debris, which will accelerate the wear between the piston and the cylinder, and at the same time block the oil passage, affecting the damping effect. In addition, the decrease in oil viscosity will cause the shock absorber to "fail" in a low-temperature environment, that is, the shock absorption effect is poor at the initial stage of vehicle startup, and gradually recovers after driving for a period of time.​

(3) Bending or Wear of the Piston Rod​
The piston rod is a core component connecting the shock absorber and the vehicle body, and it bears longitudinal impact force for a long time. If the vehicle has experienced a severe collision, rolled over potholed roads, or been overloaded for a long time, the piston rod may be bent and deformed, causing the piston to get stuck when moving in the cylinder. This is manifested as abnormal height on one side of the vehicle body or irregular shaking during driving. In addition, if the chrome-plated layer on the surface of the piston rod is worn due to factors such as stone impact, the sealing performance will be damaged, further aggravating the leakage of hydraulic oil.​

(4) Loosening or Damage of Connecting Components​
The connection points between the shock absorber and the vehicle body as well as the lower swing arm are fixed by components such as bolts and bushings. Long-term vibration will cause the bolts to loosen and the bushings to age and crack, resulting in additional "abnormal noise" when the shock absorber is working and a simultaneous decrease in the shock absorption effect. If not repaired in time, the loose connecting components will accelerate the wear of the shock absorber body, forming a vicious cycle.
 

3. Quick Judgment Methods for Shock Absorber Failure​

Car owners can initially judge whether the shock absorber is faulty through the following simple operations:​

1. Visual Inspection: After parking the vehicle, observe whether there is oil stain on the outer shell of the shock absorber. If there is obvious oil trace, it is usually a leakage fault caused by damaged seals; at the same time, check whether there are scratches or rust on the surface of the piston rod and whether the connecting bolts are loose.​

2. Press Test: Park the vehicle on a flat road, press one side of the vehicle body hard with your hand, and observe the rebound of the vehicle body after releasing it. Under normal circumstances, the vehicle body should only rebound 1-2 times and then stabilize; if the number of rebounds exceeds 3 times or there is obvious shaking, it indicates that the damping force of the shock absorber is insufficient.​

3. Driving Sensation: During driving, if you find that the vehicle jolts violently when passing speed bumps or potholed roads, the vehicle body shakes obviously, or the side tilt increases when turning, you need to be alert to shock absorber failure; in addition, if the tire has irregular wear (such as excessive wear in the middle or edge of the tire tread), it may also be related to the abnormal wheel alignment caused by shock absorber failure.

4. Professional Maintenance and Daily Prevention Measures

​(1) Selection of Maintenance Plans​

1. Slight Oil Leakage: If there is only a small amount of oil seepage and the shock absorption effect has not decreased significantly, the seals and hydraulic oil can be replaced to restore the function of the shock absorber; however, it should be noted that this method is only applicable when there is no obvious wear on the cylinder and piston rod, and a damping force test is required after maintenance.​

2. Severe Damage: If the shock absorber has a bent piston rod, worn cylinder, or severe oil leakage, it is recommended to replace it with a new one directly. It should be noted that shock absorbers are usually recommended to be replaced in pairs (that is, replacing both the left and right sides of the same axle at the same time) to avoid unbalance of the vehicle body due to the difference in damping force between new and old shock absorbers, which will accelerate tire wear and damage to chassis components.​

3. Maintenance of Connecting Components: If the bolts are loose, they need to be tightened according to the standard torque; if the bushings are aging, they should be replaced in time to avoid affecting the service life of the shock absorber due to bushing failure.​

(2) Daily Use and Maintenance Suggestions​

1. Avoid Severe Road Conditions: Try to avoid potholed and gravel roads, slow down when passing speed bumps to reduce the impact force on the shock absorber; avoid long-term overloading of the vehicle to prevent the piston rod from bending and deforming.​

2. Regular Inspection and Maintenance: It is recommended to check the status of the shock absorber every 60,000 kilometers or 3 years, including the appearance, connecting components, and oil condition; for hydraulic shock absorbers, the hydraulic oil can be replaced every 80,000 kilometers to extend their service life.​

3. Correct Vehicle Parking: When parking the vehicle for a long time, choose a flat site to avoid one-sided stress; if the parking time exceeds 1 month, the vehicle body can be properly raised to reduce the static pressure on the shock absorber.

5. Conclusion

The failure of automobile shock absorbers is not a sudden fault but an inevitable result of wear and aging during long-term use. By conducting regular inspections and using the vehicle correctly, car owners can effectively slow down the damage speed of the shock absorber; once a fault is found, it is necessary to choose a maintenance or replacement plan based on the degree of damage to avoid greater safety hazards caused by minor faults. Attaching importance to the maintenance and repair of shock absorbers can not only improve the driving comfort but also ensure the overall stability of the vehicle chassis system, building a solid line of defense for driving safety.