The automobile half shaft is the drive axle, which connects the differential and the drive wheels, and is an important part of the automobile transmission system. The structure of the automobile half shaft depends on the structure of the driving wheel. According to the force of the half shaft, the half shaft is divided into a full floating half shaft and a half floating half shaft. Many people wonder if the half-axle should be replaced by a pair. Many people in the online reviews said that they should replace the pair, saying that not replacing the pair will affect the car. But in fact, the semi-axles on both sides of the car are independent of each other. It is good to replace which side is damaged, and it does not need to be replaced in pairs. What sound will happen when the half shaft is broken? The sound of metal friction or metal collision from a motor vehicle is a characteristic of the initial stage of damage to the axle shaft. Specific manifestations are: 1. It can feel the body shake violently when driving; 2. There will be abnormal noises when turning the steering wheel, that is, metal friction sound; 3. Strong shaking can be felt when driving at high speed. If the semi-axle of the rear wheel of the front-wheel drive vehicle is good, there will only be a sound of metal rubbing or metal bumping. If the front half-axle of the front area car is good, the right front wheel is good, no power, and the left front wheel is good, and the sound is similar to the broken rear. What are the symptoms of a broken front axle of a car? 1. If the front wheel axle of the car is broken, the following symptoms will appear: bumpy road sections, rattles; the car is unstable, swinging from side to side; the brakes are off-track; direction failure. 2. The semi-axle is too large, and it is easy to break when subjected to impact load. Repair as soon as possible to avoid danger. 3. The outer ball head refers to the hand lever ball head, and the inner ball head refers to the steering gear rod ball head. The outer ball head and the inner ball head are not connected together, but work together. The ball head of the steering machine is connected to the horn, and the ball head of the hand lever is connected to the parallel rod.