Motorists who operate cars with front-wheel drive or all-wheel drive know about one problematic place - CV joints (popularly called grenades). This abbreviation hides the following concept - constant velocity joints. This device is a special bearing, in the cages of which special transverse grooves are made, and between them there are balls. This design allows you to transmit torque at different angles (up to 70 degrees).
Since the car is constantly subjected to significant forces during operation, including the transmission of torque, this unit sooner or later fails. A groove appears at the tangent points of the balls and clips, which gradually increases the gap between them, and it comes out with a certain crunch from the front of the car as it moves.
Having studied most sources, it should be noted that all structural elements of angular velocity joints are made of high-quality alloys and are subject to slow wear. However, grenade malfunctions can appear even on a new car.
Most common causes of malfunction of this vehicle unit are:
Basic sign of constant velocity joint malfunction- this is a crunching noise made by the bearing balls along the grooves. When the car starts to move, slight jerks and play may appear. When driving at a speed of over 40 kilometers per hour and hitting a depression in the road, which will rock the front part of the car so that the body points upward and the wheelset touches the asphalt, a cracking sound occurs. Also, this crackling noise occurs when entering a turn at speed with the gear engaged, when one part of the body is pressed to the ground, and the other, on the contrary, rises.
The crunch and crack of a grenade can be seen in the video:
Each drive wheel has its own CV joint. It consists of an internal and external hinge. The internal one rotates by a shaft coming from the gearbox, and the external one transmits force from the axle shaft to the wheel hub. The outer one fails more often, since the rotation angles and loads on the hub are much greater. Checking its serviceability is quite simple, you just need to drive through snowdrifts, holes or ditches. In other words, hang out the front part of the body.
