The technical condition of the suspension can be assessed while the car is moving. When driving at low speed on an uneven road, the suspension should work without knocking, creaking or other extraneous sounds. After driving over an obstacle, the car should not swing.
Advice: It is better to combine the suspension check with the check of the condition of the tires and wheel hub bearings (see "Hubs, disks and tires - technical condition check"; one-sided tread wear on the outer or inner side of the tire indicates a malfunction in the wheel alignment angles in the front suspension).
To carry out the work you will need an inspection pit or overpass.
Sequence of execution
1. Prepare the car for work (see "Preparing the car for maintenance and repair").
2. Using your hands, rock the upper part of the front wheel of the car in the transverse direction. Similarly, check the front suspension on the other side of the car.
If there is any play (even barely noticeable), then we check the reliability of the fastening of the steering knuckle to the front suspension strut and the condition of the hub bearing (see "Hubs, disks and tires - technical condition check").
Recommendation: It is better to check the functionality of the shock absorbers after a long trip, while the working fluid in the shock absorbers has not cooled down.
3. Vigorously swing the front part of the car body in the vertical direction. If the body continues to oscillate due to inertia (more than two movements - up and down) after it has stopped swinging, then one or both shock absorbers are faulty. To identify the faulty shock absorber, repeat the test, applying force first on one side of the car, then on the other.
Note: This test can only detect faulty shock absorbers. The effectiveness of shock absorbers in damping vibrations can only be tested on a special stand.
4. Inspect the suspension struts - no fluid leaks from the shock absorbers are allowed.
Recommendation: Shock absorbers should be replaced in pairs, even if the second shock absorber of the front suspension is in good condition.
5. Visually check the condition of the ball joint covers (4), rubber-metal hinges of the levers and longitudinal stretchers (2), cushions (1) and struts (3) of the anti-roll bar...
...cross-bracing cushions (5).
We replace hinges and cushions with one-sided rubber bulging, ruptures and cracks (see below for relevant sections).
6. Check the tightening of the nuts securing the suspension parts and tighten them if necessary.
7. Inspect the suspension parts. Deformation and fatigue cracks in the suspension parts are not allowed. Replace damaged parts.
8. Using a caliper, measure the distance between the brake disc and the transverse lever. If this distance changes by more than 0.8 mm when the body is rocked, replace the ball joint. Similarly, check the ball joint of the other front suspension strut.
(The original source is published on the website VazBook.ru)