Mercedes Benz R350 hits the direction in situ and what is the situation of the front wheel tire shak

1. The positioning angle of the front wheel is inaccurate, and the toe is too large;

2. The air pressure of the front forum is too low or the tire is unbalanced due to repair and other reasons;

3. The front spokes are deformed or the number of tire screws is different;

4. The installation of transmission system parts is loose;

5. The transmission shaft is bent, the dynamic is unbalanced, and the front shaft is deformed;

6. The shock absorber fails, the stiffness of the front leaf spring is inconsistent, and the frame is deformed.

Diagnosis and elimination of high-speed vibrations:

1. There are two situations of high-speed vibration, one is that the vibration is strong with the increase of vehicle speed, and the other is that the vibration occurs during a certain higher speed period, which causes the steering wheel to shake. When judging, the drive axle is erected first, the front wheel is plugged with safety plug blocks, the engine is started and the high-speed gear is gradually shifted, so that the drive wheel reaches the final test vibration speed. If both the body and steering wheel shake at this time, it is caused by vibrations caused by the drivetrain.

Because the front axle is in a stationary state at this time, if the final test vibration speed is reached, the car does not shake, the cause of vibration is the fault of the front axle part of the car;

2. Check whether the positioning angle of the front wheel and the front wheel meet the requirements, and if it is inaccurate, it should be adjusted;

3. Set up the front axle to test the wheels, check the static balance of the wheels and whether the tires are too deformed. If necessary, a good wheel can be changed for comparative experiments.

Analysis of the causes of car shake:

1. Cold start jitter.

First of all, starting from the cold start, the main reason for the cold start body shaking is that the fuel combustion is insufficient, resulting in insufficient power of the car. The ignition energy is low, and when starting, especially when the temperature of the fuel and lubricating oil is low, more oil is required to meet the power. Over time, the pole gap of the spark plug gradually increases, resulting in a decrease in ignition energy and poor fuel atomization, which leads to the shaking of the body.

In addition, the ignition energy can also be reduced due to the aging of the ignition coil, the aging of the high-voltage wire of the spark plug, or the leakage of electricity.

2. Suspension system problems.

Body shake is also related to the aging of the suspension system. It is mainly responsible for filtering out the shake of the engine when it is running, and if there is a problem with the suspension, these vibrations will be transmitted directly to the steering wheel and cab, affecting the driving. When the engine is idling, it is easy to cause shaking when the electrical system in the car is turned on.

The engine will increase the load when the electrical appliances are turned on, causing the idle speed to drop, and to compensate for the jitter caused by the idle slip, the engine will automatically increase the speed by partially. So, when the electrical system, especially the air conditioner, is turned on, the engine will often shake. This jitter is likely to be caused by the aging of the shock absorber and needs to be replaced in time.

3. Tire problems.

For tires, the tire must be balanced once when the car is replaced with new tires and new steel rims, otherwise the steering wheel will be prone to shake when the counterweight is uneven. If you find that the tire weight is not equal, you need to add lead to the inside of the rim to average the weight of the tires on both sides. Whether it is a general steel ring or a lightweight aluminum ring, it may deform or crack when subjected to a certain external force.

Deformation of the rim can cause shaking when driving, uneven weight of the rim can also cause shaking when driving, and incorrect angle of the rim can also cause shaking when driving.

4. Throttle problems.

The most common cause of car shake may be a dirty throttle valve and excessive carbon build-up in the fuel injector. After the car travels for a period of kilometers, the throttle valve will be too dirty to cause the throttle to close loosely or the idle motor to stagnate, resulting in the engine idling speed is too high, and the carbon deposits generated by the engine in this process will also cause the vehicle to shake, especially when starting the vehicle, the engine will shake more than normal, and even sometimes there will be a phenomenon that can not be started at one time. Therefore, when the body shakes, the first thing to do is to check the throttle and fuel injectors.

If you find that the throttle valve is too dirty or the fuel injector has too much carbon deposit, you should clean it with fuel injector cleaner or throttle cleaner in time.

5. The oil pressure is unstable.

If you still find that the body shakes after these are finished, it is recommended that you go to the repair shop to check whether the fuel supply pressure and intake pressure sensor are normal, if the oil pump supply pressure is not normal, the intake pressure sensor is wrong and improper work will cause the body to shake.