Dear motorists! Before we discuss the topic of checking shock absorbers, let's remind ourselves and those who do not yet know what shock absorbers are and why they are an important part of the suspension of our cars.
What are the consequences of a faulty shock absorber?
Shock absorbers (dampers) are devices that serve to dampen vibrations during the movement of a car (damping) by converting mechanical energy into thermal energy. Shock absorbers act in combination with such vehicle suspension elements as springs, springs, torsion shafts, pillows, etc.
Shock absorber diagnostics should be carried out systematically by the driver. Why, you ask, because MOT was completed, and everything was fine. Unfortunately, like everything in this world, shock absorbers tend to fail. And the sooner the driver notices a malfunction of the shock absorber, the less money will then be spent on restoring the consequences.
The most important thing to remember is that a systematic check of the shock absorbers yourself takes a couple of minutes, and can save you trouble with other car systems.
- A faulty shock absorber in combination with wheel imbalance (you understand that there simply cannot be perfect balance) leads to intense and fast. Add broken wheel bearings here, specify the cost of the tire and bearings - your budget will not like the figure.
- A faulty shock absorber causes the rest of the suspension parts to fail. After all, the suspension is designed for the operation of all elements in the complex. For example, after several thousand km. the strut support bearing may fail.
- The serviceability of the shock absorber directly affects the service life of the brake system, in particular. If you are not interested in conducting, then timely diagnosis of shock absorbers will help push this procedure forward.
- A faulty shock absorber is, which means that a few extra meters can lead to an accident. And here you can count, not count - your body repair and ... you don’t even need to think about it. And you just need to check the shock absorbers in time.
How to check shock absorbers without a diagnostic stand?
Many motorists with a "smart" and thoughtful look shake the car by the fender. Other motorists, observing this picture, understand that shock absorber diagnostics are taking place. But, both those and others have a poor idea that such a diagnosis does not give any results.
The fact is that the body will swing only when the shock absorber is forever dead, and if it still “breathes” a little, then the shock absorber will pass such diagnostics. But, you don't need it.
The most proven way to diagnose shock absorbers is through the eyes and ears of the driver. By visual inspection, we determine oil smudges (although the dryness of the shock absorber is not always an indicator of its serviceability). By ear, you determine the knock in the suspension. If you are confident in the suspension, then only the shock absorber can make a knock.
There is a subjective test that answers the question of how to check shock absorbers - these are tests in motion when passing the same turn at the same speed. To do this, you need to have some experience driving this particular car. If the car blows away in a turn, it's time to go to the car market for shock absorbers.
Testing at the stand, of course, costs some money. Your money. Therefore, before driving a car to the stand, find out for yourself:
- The stand computer can be tuned to your car model or to a similar suspension.
- How is the lifespan of a car calculated? Over time, the rigidity of the body changes, respectively, a 10-year-old car will not fit the factory standards for depreciation. And the stand will show it.
- Before checking, it is necessary to check the wheel alignment and tire pressure.
Diagnostics of shock absorbers is not an easy task, but it is worth it, since a lot depends on a working shock absorber. First of all, the serviceability of the car, and.
The results of the influence of the shock absorber on the performance of the car
Braking distance at a speed of 100 km / h: before replacement 51.5 m, after - 47.5 m.
The maximum speed for passing the "reference" turn before replacement is 84 km/h, after - 105 km/h.
Expert opinion
Ruslan Konstantinov
Automotive expert. Graduated from IzhGTU named after M.T. Kalashnikov with a degree in Operation of Transport and Technological Machines and Complexes. Over 10 years of professional car repair experience.
After the decision has been made to change the shock absorbers, you should know some rules for choosing new parts. They must be checked before buying, but many do not know how to do this. Often there are unpleasant situations when a frank fake turns out to be in a beautiful box.
The first thing to do is to conduct a visual inspection, you should compare the conformity of the markings and identify obvious signs of malfunction. The next method is the measurement of parts for compliance with geometric parameters. With the help of a ruler, the length of the rod in the raised state is checked, the stroke and diameter of the rod are measured. It is also important to check the shock absorbers for performance. It is very simple to do this, just squeeze the stem all the way down and pull it back. The rod should move smoothly, without jerks and extraneous sounds. If you need to check a two-tube shock absorber, then in this case you first need to pump it several times and set it to a vertical position, the shock absorber should stand like this for a while.
Do not treat shock absorbers negligently, because safety on the road depends on it. If these parts are faulty, the car may simply become uncontrollable when cornering and during braking. In addition, such malfunctions can provoke a rollover of the car.
So draw your own conclusions. Good luck to you car lovers.
Rocking a car is one of the easiest and most common ways to check shock absorbers. Its main essence lies in the rocking of the car on each side in turn. There are a couple of different ways to test shock absorbers using this method:
- In the first case, the owner, after a single pressure on his car, observes the movement of the body. If it returns to its original position slowly, then the shock absorbers are working, but if the body shoots up sharply without delay, they do not work.
- The second method of this test involves a fairly intense buildup of the machine. If the shock absorbers are fully operational, after the end of the swing, the body stops already on the first or second inertial roll. Accordingly, the worse the condition of the shock absorbers, the longer the vibrations die out.
Visual inspection is perhaps the most unreliable of all the ways to check the performance of shock absorbers, we read,. First of all, it helps only in identifying traces of oil on the surface of the strut housing, which are evidence of loss of tightness and failure of the shock absorber. But often, due to a large layer of dirt, it is very difficult to find the exact cause of the appearance of oil on the body, so the desired shock absorber should be well cleaned and re-inspected after a couple of days of operation. And only with the repeated occurrence of oil leaks, it will be possible to talk about a malfunction of the spare part.
Checking the performance of a shock absorber by the degree of heating of its body is rarely used by car owners. This can be explained by the extreme inconvenience of such a check, since almost all shock absorbers are located in very hard-to-reach places. The principle of operation of any hydraulic shock absorbers is based on the conversion of vibrational energy into heat. From which it follows that a warmer shock absorber performs its function more efficiently.
But to accurately assess the health of shock absorbers by the behavior of a moving car, the most experienced drivers can do it. With non-working shock absorbers at a speed of about 85-95 kilometers per hour, the car begins to scour noticeably along the highway, some longitudinal and even transverse buildup appears, and a decrease in directional stability is observed.
Of course, the most accurate way to determine the condition of the shock absorber is bench diagnostics. There are two main methods for this verification. The first one is carried out directly on the car, having previously installed it with wheels on the working planes of the vibration stand.
Good day, dear motorists! Before we get down to business with the question of how to check the performance of the shock absorber, not entirely pleasant news.
Of course, news for those who are not yet in the know. The method of checking the health of shock absorbers, by the method of swinging the body of your car, has sunk into oblivion.
Once upon a time, on old models of the classics with past models and types of shock absorbers, body buildup could determine whether the shock absorber was working or not. The complex design of a modern one will not allow you to make an objective conclusion about the health of the shock absorber by eye.
Then you have a reasonable question - how to check the health of the shock absorber.
What to Expect from Defective Shock Absorbers
You remember that shock absorbers, in combination with other suspension elements, are responsible for damping vibrations of the body and wheels, allow the wheels to interact reliably and safely with the road, and prevent the creation of uncontrolled rolls of the car.
The main malfunction of shock absorbers is a change in their performance, which occurs due to: leakage, wear or mechanical damage to the working parts (rod) of the shock absorber.
What are the consequences of failing shock absorbers?
- vehicle control disorder. Remember the phrase "lost control ...". She surprises, sometimes. How can you not deal with it? The answer is simple: faulty shock absorbers made the car at speed, yes when cornering, just a spontaneously moving pile of metal;
- an increase in the braking distance, the likelihood of "leaving" to the side during medium or extreme braking;
- decrease in vehicle directional stability;
- reduction in carrying capacity;
- acceleration of wear and failure of such suspension elements as: springs, strut supports, hub bearings, silent blocks, CV joints, etc. That is, the probability of failure of the suspension, accelerates in time;
- deterioration in the comfort of movement in the cabin. Your, by the way, comfort, when all the bumps in the road, in which we have no shortage, you feel on yourself.
How to check the health of the shock absorber
Important! It will be a question of how to check the health of the shock absorber, but not the performance. Efficiency, that is, the compliance of the shock absorber with the manufacturer's technical specifications, is a separate conversation.
You can check the health of the shock absorber on your own only by visual inspection. During a visual inspection without dismantling the shock absorber, you can determine the serviceability of tightness and the presence of mechanical damage (dents).
Namely, if there are oil smudges and drops on the shock absorber body, immediately conclude that the seals have become unusable. This indicates an imminent failure and need.
The existing version that the presence of oil "fog" on the case is a malfunction is somewhat erroneous. This plaque during the operation of the shock absorber is considered normal.
If you are diagnosing a shock absorber after removing it, then you should pay attention to the rod: there should be no signs of corrosion, scoring, and, moreover, deformation of the rod.
How to check the performance of a shock absorber
That is, how to check whether the characteristics inherent in this mechanism correspond to the requirements for the shock absorber to perform its direct functions. This type of shock absorber diagnostics can only be carried out using instruments or on special stands.
- Device with displacement sensor. Device "manual". It is attached to the fender of the car, and the sensor is placed on the ground. The body swing method is used to collect data. At the same time, factory parameters are entered into the device, which correspond to the standard of the shock absorber. The performance of the shock absorber is determined as a percentage.
- shock-test(shock test) is carried out at the stand. The axle wheels are raised and lowered sharply. The computer records the damping factor of the shock absorber.
- Express diagnostics(hard braking). It is held at the stand with platforms. At the same time, efficiency is also diagnosed. The car enters the platform and brakes sharply. There is a fixation of body vibrations and the load on the platform sensors. The accuracy of this method leaves much to be desired.
- In addition, there are stands for checking the performance of shock absorbers using the amplitude-resonant method.
Each of these methods shows the coefficient of effectiveness of shock absorbers, on the basis of which it is possible to make a decision about the performance of the shock absorber and the need to repair or replace it.
How to test new shock absorbers
It would seem that it is easier. I came to the store, they give you a new shock absorber in the package (a pair, since a prerequisite for replacing a shock absorber is replacing a pair on one axle).
Easier, but not much. Many manufacturers have learned how to make beautiful packaging, but do not burden themselves with instructions describing the technical characteristics of shock absorbers.
You can check the new shock absorber on the stand, but ... only after purchase. Therefore, the old-fashioned way of checking a new shock absorber remains.
- Visual, external inspection. We check the label. Which must match the manufacturer's catalog. We check the shock absorber for mechanical damage to the body, rod, seals, etc. check threaded connections. Naturally, there should be no talk of any smudges of oil.
- Geometric fit check. You will need a ruler and a caliper. We check the length in the shifted state, the stroke of the rod (we are guided either by the manufacturer's recommendations, or the deviation from the nominal values \u200b\u200bcan be within ± 5 mm). Rod diameter.
- Checking the performance of the shock absorber. One-pipe can be checked without prior preparation. Compress and stretch the shock absorber 3-5 times. The movement of the rod must be smooth, with the same effort, without jamming and sudden shocks. There should be no extraneous noise or squeaks, except for the natural "sniffling". This is the result of fluid flowing inside the shock absorber. The two-pipe one must first be prepared, namely: pump it 3-5 times, then place it vertically, the stem up, and after that do not put it down or turn it over.
Good luck with diagnosing the health and performance of shock absorbers.
A good driver feels how the car behaves on the road, and by some signs it reveals which system to diagnose. When the bumps on the road began to be felt more noticeably in the cabin, then most likely it was time to check the suspension or its individual elements.
There are several ways to check shock absorbers on a car without dismantling. They will not give a final verdict, but they will provide a sufficient amount of information about their condition.
The purpose for which these hydraulic struts are installed is to dampen vibrations, so they must be checked regularly. Reliable shock absorbers, in addition to eliminating the buildup of the body, ensure the interaction of the wheel and the road, and also eliminate the formation of unauthorized rolls of the car.
Before checking the performance of the shock absorber, you need to know that the main reasons for their failure are mechanical damage or wear of individual elements, as well as depressurization of oil cavities. Such problems lead to common consequences:
- a significant increase in the braking distance, as well as a car can lead to the side during emergency braking even at medium speed, such troubles are fraught with a significant decrease in safety for both the driver with passengers and other road users;
- decrease in car controllability, the car can involuntarily drive in different directions, so driving even at low speed will be risky;
- reduced carrying capacity, since even a light load or several passengers will significantly “land” the car;
- a decrease in comfort while driving, even on a quality road, which will become noticeable in the rocking of the body;
- it is necessary to check the shock absorber struts for operability in order not to contribute to the rapid failure of other suspension elements, such as supports, bearings, springs, etc .;
- increased tire wear (usually uneven) due to imbalance;
- this problem directly affects the intensive wear of the brake system, pads, discs.
Suspension Diagnostics
serviceability
Before you check the rear or front shock absorbers for serviceability, you need to understand that this parameter in a garage without the appropriate equipment can only be checked visually. In this case, the result will not be one hundred percent. With the help of inspection without removing the rack from the car, the driver is able to assess the integrity of the stem, the presence / absence of the consequences of mechanical damage, or a clear and recent depressurization.
For gas suspension elements, it will be problematic to determine depressurization “by eye”. Here other methods are needed.
Problem shock absorber
Oil smudges or drops on the body of the hydraulic parts are an indication that the sealing elements are damaged. The car owner needs to take care of the quick replacement of problem racks. When removing them from the car, you need to check the condition of the rod, which should not have corrosion spots, wear, curvature, or metal scuffing.
performance
Banal rocking by pressing on the fender of the car, and then a sharp release, is not able to form a clear picture of the state of health of the shock absorbers. It is generally accepted that with a good suspension, the car will not sway. However, this test does not always allow you to understand the condition of the struts, sometimes even with heavily worn elements, the suspension springs quite clearly, and the car does not sway. So you can identify only completely empty and non-working shock absorbers.
Quality racks
It is easier to identify this problem in motion. A car with a working suspension can knock while driving, most often in the presence of bad struts. Short extreme driving is also allowed, which can reveal problems in the suspension. The car in such a situation does not hold a turn well, weakly adheres to a rectilinear trajectory of movement.
If there are stands, the result will be more accurate. There are several types of testing:
- The device is mounted on the wing of the car, and the second part is placed on the floor nearby. The buildup of the body gives a small amplitude and automatic measurements take place, which are compared with factory indicators.
- During shock tests on the stand, the axles being tested are raised and then abruptly released. The electronics at this time calculates the attenuations and compares them with the reference values.
- The platform for hard braking makes it possible to determine the load on the sensors during the process. However, this test is less accurate than the previous ones.
Bench test
Amplitude testing methods are also used.
Checking new shock absorbers
A good car owner should put quality components on his car.
Choosing the Right Shock Absorbers
In order not to make a mistake with them, you need to check them for compliance with elementary standards before buying.
- Outer part. There should be no oil on the surface, and the marking must correspond to the catalog parameters. The body must be without mechanical damage, the stem is even, the thread is cut with high quality.
- Geometric parameters. With the help of a tape measure and calipers, we take measurements for compliance with those installed in your car and those offered in the store. Permissible length deviations must be within 5 mm.
- The performance of the new shock absorber. Compressing / decompressing several times should not create shocks or jams. The applied force on compression / expansion of a high-quality rack will be the same during several receptions.
Conclusion
Shock absorbers that are out of specification should be replaced as soon as possible. Driving safety depends on them. An accurate test result can only be obtained with the help of quality tests, although an experienced driver will reveal the inoperability of the racks during extreme driving. Even when buying this suspension element in a store, you need to check them for performance and compliance with the specified characteristics.
These subtle and almost invisible devices under the body not only make driving comfortable, your safety and health directly depend on them.
Visual diagnostics
Take a close look at the appearance of the shock absorber. If traces of oil leakage are visible on the body of this device with the naked eye, this indicates a violation of the tightness of its chamber due to wear or damage to sealing elements, for example, oil seals.
The damping properties of such a device will either be below the norm, or will be completely absent.
Even a slight deformation of the shock absorber body can lead to difficulty in the stroke of the piston or to its complete stop due to jamming.
The fasteners of this damping device must not be broken or damaged by corrosion, and the rubber pads and bushings in the lower hinge must be intact, with no visible signs of destruction.
The shock absorber rod should sparkle with a perfectly mirrored surface. If this is not the case, then the piston stroke of this device is completely absent and the shock absorber does not at all perform its functions of damping suspension and body vibrations.
In many cases, tires serve as indicators of the technical condition of shock absorbers. They may indicate a malfunction of the depreciation devices.
Checking the removed shock absorber
Place the dismantled shock absorber vertically and, fixing its lower bracket with your feet, pull it out several times with your hands, and then lower its rod down. In a serviceable shock absorber, the force of resistance to moving the rod up should be many times greater than the force of resistance to moving the rod down.
In simpler terms: the rod should go down relatively easily, and go up - with considerable effort.
If the rod moves equally easily in all directions, then there is very little fluid in the shock absorber cylinder or it is completely absent there.
A decrease in resistance to movement of the rod in its positions close to the extreme ones will eloquently indicate the presence of air in the working cylinder of the shock absorber.
Checking damper rebound
You can check the condition of the car's shock absorbers by rocking the front and then the rear. A car with faulty shock absorbers will make more than one swing cycle, but in the case of a jammed shock absorber strut, it will not be possible to swing the car at all.
But this method of verification cannot always correctly assess the state of the damping devices. This applies to cars with new types of suspensions.
Assessment of the state of shock absorbers according to the nature of the movement of the car
If, when braking a car, when cornering, on a wet and slippery road, or under the influence of a strong side wind, the car constantly sways from side to side, and reacts reluctantly and late to steering movements, there is only one conclusion - it's time to change the shock absorbers to.
Do not neglect the control over the technical condition of the shock absorbers of your car throughout the entire period of its operation.
Be aware that a car with faulty shock absorbers becomes difficult to control, when braking, its braking distance increases significantly, and maneuvering can lead to rocking and roll, or even the end of the car.
Good luck to you! Not a nail, not a wand!
