The condition of components and parts of the chassis affects the steering of the car, its stability on the road, as well as comfort and driving safety. The chassis is continuously subjected to static and dynamic loads of various magnitudes and intensities. Therefore, units and parts that make up its structure require constant control and diagnostics of the state, and in case of failure – prompt and professional repair. If it is not profitable to repair the machine as a whole, it should be scrapped:

Maintenance of the chassis involves a whole range of diagnostic, adjustment and repair operations, among which, in terms of its significance and relevance, replacement of the ball bearing unit takes priority place. Wear or breakage of the ball bearing support (ball pin) can cause serious problems, expressed in the loss of controllability of the vehicle. It is important to remember that the ball bearing support is the part, failure of which requires an immediate response.

Design and function

The ball bearing is designed to provide the moving connection between the wheel hub and the suspension arm. The ball bearing is a ball and socket joint that allows the wheel to turn. By its design, the ball stud is a metal rod (cylinder) with a spherical cap pressed into the housing. The lack of backlash and tightness of this ball joint is provided by plastic inserts and a protective rubber cover (dust cap).

The essence and causes of failure

Ball joints, as running gear components, experience considerable shock loads, as a result of which the plastic liners are destroyed, there is a gap between the pin and the body of the support. Causes of accelerated wear and replacement of ball bearings are, as a rule, the following:

Strong shock: collision with an obstacle, getting into a pit

Dust and dirt penetration into ball bearing: destruction of protective rubber dust shell

manufacturing defect

Do not disregard the fact that, as all car parts, ball joints are subject to natural wear. The diagnostics of the state of details of suspension and suspension elements should be performed at least once a year or after the run of 10-15 thousand kilometers, whichever event occurs first.

With severe wear on the rubbing surfaces of the ball bearing and, as a consequence, the appearance of a significant gap, shock loads may lead to the destruction of the ball joint.


Characteristic signs signaling that the ball bearing must be replaced are:

distinctly audible knocking when driving on uneven pavement at low speed

squeaking and rustling when turning the steering wheel around a hub

wobble of front wheels when driving on a straight section of road

uneven wear of tire treads;

Final conclusion about suitability for further operation of ball bearings is made on the basis of visual inspection: check the integrity of rubber dusters, the presence of radial and axial clearance. You should know that replacement of ball bearings is performed in pairs, on both wheels. After installing the new parts of the running gear, the wheel camber adjustment must be carried out in a mandatory manner.

It is also important to remember that comprehensive maintenance of the chassis must be performed exclusively by professionals, using modern diagnostic and repair equipment, original spare parts and consumables.