Cheap, reliable and practical. Visual inspection for the diagnosis of shock absorbers is a mandatory procedure. If you find a way to look at the shock absorbers, then at least traces of oil on the shock absorber body can be noticed immediately. In order to make sure the diagnosis is correct, just wipe the shock absorber with a rag and repeat the inspection after a few days. If the car is on a lift, then try to assess the condition of the shock absorber rods at the same time: they should sparkle! Traces of rust or other ugliness are a sign of malfunction.
Tires can also tell about problems with shock absorbers. Uneven wear spots hint at a malfunction. It is also worth assessing the condition of the protective kits (anthers) and springs, then the upper supports. Well, ideally - and all other elements of the suspension. But here you already need an experienced eye.
Unfortunately, a defective shock absorber itself may not have any external signs of wear. Its inefficient operation can be caused by the wear of internal components and materials: it is visually impossible to calculate this. In such cases, other diagnostic methods should be used, as well as the actual period of its operation.
Not the most accurate, but the most popular and obvious way to diagnose. It is necessary to energetically swing the front / rear of the car, then relieve the load and observe how quickly the body stops swinging. If, after removing the load, he will make more than one step of buildup, it means that the buildup was done not in vain: the shock absorber, alas, crappy … The only trouble is that in this way you can determine a completely “dead” product, and even if you have the proper experience. It is another matter if the shock absorber tightly jammed: it will be determined instantly, since it simply will not be possible to swing the car.
Try not to overdo it during the buildup, so as not to damage the body parts - it happens and this …
If while driving a car suddenly gains some independence - it scours on bumps, sways in all directions, reluctantly reacts to the steering wheel, then shock absorbers are most likely to blame. Contrary to popular belief, this is manifested not only at high speeds, but even if the speedometer is quite "urban" numbers. At the same time, you do not need to write out a pretzel on the road - in a quiet place there are enough exercises such as acceleration, braking, a snake … In any case, if the car's handling has deteriorated over time, you should contact competent specialists for diagnostics.
For an example, you can see in this video how cars with serviceable shock absorbers behave and not.
4. To measure
The easiest, rather quick and not so expensive way to get general information about the effectiveness of the suspension is to call in at the diagnostic stand, take measurements and listen to the verdict.
Another question is how accurately the sentence will relate directly to shock absorbers. The fact is that in the case of various kinds of “shakes” (of which there are more and more recently), the presence of at least one faulty element (not necessarily a shock absorber) will significantly affect the final results of the efficiency indicator. In addition, the algorithms that evaluate the performance of the suspension are different, and the diagnosis of one car at different stands can lead to the fact that the received data on the state of the suspension can vary.
There are cases when, when diagnosing a car on a “shake” with a working suspension and recently replaced shock absorbers, the data obtained indicated a low residual suspension efficiency. But with a "test drive" the car behaved perfectly. The reason is that the stand was not designed for more “tough” tuning of shock absorbers of the tuning series in comparison with the characteristics of the original products, as a result - an incorrect sentence. Well, it happens.
A very important point! The final indicators may be affected by such parameters as tire pressure, vehicle loading during diagnostics, small deviations from a straight line when entering a stand (appearance of a deviation angle from the longitudinal axis), accidental installation of a car on a handbrake, uneven loading of a car during diagnostics, etc..d. It will be a real pleasure for the negligent master to “dissolve” the client for the cost of new shock absorbers, so that, as a matter of fact, he accidentally pumps up a flat tire to him …