How and why to pump shock absorbers before installation

Shock absorbers, what they are needed for and where they are installed

When accelerating, the vehicle “squats” backward, unloading the front wheels and loading the rear wheels, which reduces their grip on the road surface. When braking, the opposite is true. In both the first and second cases, the ideal position would be one in which the machine would maintain its normal “horizontal” position.

Approximately the same picture is observed during maneuvering, however, the load here shifts along the sides of the car, and not along the axes.

Shock absorbers keep the wheels in constant contact with the road surface to prevent the driver from losing control of the vehicle. The racks are installed directly next to the car wheels.

Shock absorber malfunctions

There are a number of indicators by which you can determine that the shock-absorbing elements of your car have become unusable and will need to be replaced in the near future. Otherwise, difficulties will arise in driving the car, and the braking distance will increase.

Oil leaks

The simplest sign indicating damper wear is the appearance of oil smudges on the body, which can be determined by visual inspection.

If such signs occur, it is recommended to verify that the element in question is faulty by sharply pressing the rear fender with your hands and releasing it. If the part is working properly, the suspension will slowly sag and return to its original position. When the shock absorber is not functioning properly, the rear of the vehicle will bounce on the spring, quickly returning to its original position.

Video: identifying a faulty damper without removing it from the car

Knock and squeak when driving

The most common cause of knocking in shock absorbers is fluid leakage. If there are no signs of leakage, it is necessary to carry out the test described above with the machine rocking. The knocking noise may also be the cause of damper wear. If a part has traveled more than 50 thousand km, then you should think about replacing it. Common causes of knocking also include air entering the outer cylinder of the damper due to an oil leak. You can try to fix the problem by bleeding it. If, while the car is moving, a squeak is heard from the rear suspension, then the cause of the malfunction may be worn rubber bushings of the upper and lower shock absorber lugs.

Uneven tire wear

Problems with shock absorbers can also be noticed by uneven tire wear, which significantly reduces their service life. This is explained by the fact that while driving with a faulty damper, the wheels often come off the road surface and cling to it again. As a result of this process, the rubber wears unevenly. In addition, you can notice wear in the form of patches, which is due to imbalance of the wheels. Therefore, the tire tread condition must be periodically monitored.

Sluggish braking

If the shock-absorbing elements are faulty or there are problems in their operation, the contact of the wheels with the road surface worsens. This leads to short-term tire slippage, reduced braking efficiency and increased brake pedal response time, which in some cases can lead to accidents.

Plunging and pulling of the car to the sides when braking

Malfunction of the shock absorber valves, as well as wear of the seals inside the product, can cause noticeable swaying of the body when you slightly press the brake pedal or move the steering wheel. A clear sign of a malfunction is strong body roll when cornering, which also often requires steering. A malfunction of the shock-absorbing elements is also indicated by dives of the front or rear of the car during sudden braking, i.e., when the front end drops strongly and the rear lifts up. The vehicle may pull to the side, for example, if the rear axle is not installed level. This is possible when the longitudinal rods break and subsequent poor-quality repairs occur.

Car instability on the road

If the “seven” behaves unstably while moving and is thrown to the sides, then there may be many reasons for this behavior. It is necessary to inspect the condition of the elements of both the front and rear suspension, as well as the reliability of their fastening. Regarding the rear of the car, it is worth noting that attention should be paid to the condition of the shock absorbers, rear axle links, and rubber seals.

Shock absorber ripped out

Sometimes VAZ 2107 car owners encounter such a problem when the mounting rings of the rear suspension shock absorbers break off. This problem arises when installing spacers under original springs or springs from a VAZ 2102, VAZ 2104 in order to increase ground clearance. However, with such changes in length, the standard shock absorbers are not enough and the mounting eyes tear off after a while.

To prevent this from happening, it is necessary to install a special bracket, which reduces the shock absorber stroke.

There is another option - to weld an additional “ear” below the old damper, which will also reduce the stroke and prevent failure of the suspension element in question.

What is the difference between gas-oil products and oil products?

From the name itself it is already clear that their main difference is the working composition that is used inside the device.

In oil shock absorbers, the working space is filled with hydraulic oil.

The main disadvantage of these types of devices is aeration (oil foaming), which occurs as a result of changes in the physicochemical properties of the liquid when a piston acts on it in a small space.

This is manifested by a failure in the operation of the device and uncharacteristic sounds.

A partial reduction in aeration is achieved by replacing air with nitrogen gas; as a result, gas-oil analogues have appeared, which come in one or two pipes.

Single-pipe ones are often called gas ones, because there the oil and gas are separated by a movable jumper and do not mix.

IMPORTANT TO KNOW: Causes of shock absorber knocking. Strong backpressure ensures gas pressure in the region of 10 - 30 atmospheres; there are also adjustable analogues

Mainly installed on sports cars

Strong backpressure ensures gas pressure in the region of 10 - 30 atmospheres; there are also regulated analogues. Mainly installed on sports cars.

Twin-pipe gas-oil shock absorbers have less gas pressure - from 3 to 10 atmospheres.

But he won’t delve into the topic, because that’s not what you came here for. The shock absorber structure can be seen in the photo below.

How to check a shock absorber

If you are going to install a dismountable oil shock absorber, first open it and check the condition of the parts and the oil level. If necessary, add spindle oil or automatic transmission and power steering fluid with a low freezing point. You may be able to find “shock absorber fluid” like AZh-12T or something similar in a car store. When the rod is fully inserted, the oil level reaches the upper locking nut. Remove the cylinder. If you do not have a cylinder, but a cartridge, then adding oil or visually assessing the condition of the parts will not be possible.

Bleeding the shock absorber: why is it done?

Let's start with the fact that today there are several types of shock absorbers, among which the most common and widely used are:

• oil shock absorbers;
• gas-oil shock absorbers;
• gas shock absorbers;

Without going into details, the differences lie in what one or another shock absorber is filled with. In short, oil struts are the softest and most comfortable, while gas struts are the stiffest, but hold the road better. In turn, gas-oil struts represent an average option in terms of rigidity and stability.

You can also note the design features, since the shock absorber can be single-pipe or double-pipe. At the same time, twin-tube shock absorbers are common today; they are installed on the vast majority of cars. For this reason, we will focus on pumping racks of this type.

So, as for the pumping itself, opinions on why it is needed differ somewhat. At the same time, shock absorber manufacturers themselves necessarily recommend bleeding before installing struts on a car!

As a rule, it is generally accepted that bleeding is necessary to remove the air gap from the mechanism. In other words, if there is air in the inner sleeve, the struts will not work normally when driving a car, and the piston shocks can damage the mechanism.

A sign of a problem is that the shock absorber begins to knock. In oil-filled shock absorbers, oil may remain in the inner sleeve, the strut will not function properly after installation and may leak quickly.

However, the widespread opinion about the presence of air in the shock absorber is questioned by many drivers and experts. In fact, to understand why pumping is needed, it is enough to study the information on the official websites of the manufacturers of the racks themselves. For example, below are the recommendations of KYB specialists.

• Bleeding twin-pipe shock absorbers before installation is a mandatory procedure! In double-pipe shock absorbers, the working fluid can flow from the inner to the outer cylinder during storage of the strut, and in parallel, boost gas enters the inner cylinder.
• An under-pumped shock absorber can cause failure of the entire shock absorber piston system, which is a violation of the installation instructions and will void the shock absorber warranty!

In other words, if the strut is not pumped, knocks and noises appear after installation, and the shock absorber valves are destroyed. For this reason, before installation on a car, pumping twin-pipe shock absorbers is necessary in order to bring the struts into working condition (prepare for work), as well as to check their functionality before installation on the car.

For example, during bleeding, you can identify a jammed valve mechanism, as well as other malfunctions. The pumping itself allows the oil and gas to be properly distributed inside the shock absorber.

As mentioned above, during storage and transportation the shock absorber lies, and does not stand as on a car, it can be turned upside down, etc. Of course, the contents of the rack are not distributed properly. In turn, bleeding allows you to eliminate undesirable effects on the valve mechanisms at the very beginning of the car’s movement after replacing the struts.

What to do with used ear supports

How to pump new shock absorbers was described above, but with used ones the situation is different. Let's say you disassembled the car and removed the struts from the suspension or bought used shock absorbers - do you need to bleed them? The answer is yes, it is necessary to do this if the racks have not been used for some time. During this time, the natural distribution of the environment has been changed, so they will not be able to perform their functions as expected.

Even if the seller swears that they work properly and were only removed from the car yesterday, don’t take the risk. It's best to spend a couple of minutes preparing before putting them in place.

There is no difference in the process, except for some nuances:

1. Listen to the sound the cylinder makes as the piston moves. If a squeak is noticed, repeat the procedure 5-6 times. If the situation has not changed, then all that remains is to throw out the racks or have them serviced for restoration (it won’t be much cheaper than buying them).
2. If they work normally, then one pumping will be enough. There is no need to repeat it.

Pumpable types of shock absorbers

Surely you know that shock absorbers are divided into oil, gas and gas-oil. All of them are quite actively used in the design of vehicles.

In this case, pumping is required for all categories of suspension units:

• front shock absorbers;
• rear;
• new parts;
• used;
• original;
• analog;
• single-pipe;
• two-pipe;
• collapsible;
• non-separable.

As you can see, it doesn’t matter what kind of shock absorbers we are talking about. All of them are subject to preliminary pumping before installation. Let you have at your disposal an ordinary old Gazelle or a brand new Audi. Although owners of expensive cars often prefer to have their car serviced at a car service center. But that’s not about that now.

Although it is not fundamentally important whether the shock absorbers are rear and new, or front and used, special attention should be paid to the specific type of element. Gas, oil and gas-oil shock absorbers have their own instructions. Relying on them, you can pump the part with your own hands, and the rack will work for a long time, efficiently and efficiently

Relying on them, you can pump the part with your own hands, and the rack will work for a long time, efficiently and effectively.

Gas shock absorbers

Let's start with pumping these particular shock absorbers. The gas most often used here is nitrogen. It's not difficult to upgrade them. You just need to follow a certain sequence of actions:

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• Turn the assembly over so that the rod is pointing down toward the floor;
• Now slowly begin to compress the shock absorber;
• After squeezing, hold it in this position for a few seconds;
• Then turn the part the other way around;
• Hold the rod clamped for 4-5 seconds;
• Pull the rod back until it stops;
• Turn the shock absorber over;
• Leave the element in a horizontal position and install it on the car.

At this point, pumping is considered complete. Like I said, nothing complicated. Take your time, but also try not to keep gas-type shock absorbers in a compressed state for more than 6 seconds.

Oil shock absorbers

In the case of such car shock absorbers, the procedure is slightly different.

It is extremely important to strictly follow the given algorithm. The more accurately you follow the instructions, the higher the likelihood of doing everything as correctly as possible.

• Place the shock with the rod down, as in the case of gas elements;
• Smoothly compress the shock absorber until it stops;
• Having completed the compression, do not release the part and hold for 2-3 seconds;
• Without releasing the rod, turn the shock absorber over;
• Hold in a compressed state for up to 6 seconds;
• At this time, the air should come out;
• Then pull the rod out all the way;
• Turn the shock upside down;
• Wait about 3 seconds, and perform similar manipulations at least 3 times.

Although it is believed that the optimal number of such approaches for oil-based automobile shock absorbers is 6.

When you reach the third pumping, be sure to perform the so-called control action. It consists of the following:

• turn the shock absorber so that the rod points upward;
• make several short but sharp compressions of the rod.

In this case, the movement of a properly pumped shock absorber must be as smooth as possible, without dips or jerks. If this occurs, you need to repeat the pumping procedure.

Why is pumping needed?

In warehouses, shock absorbers are stored in a horizontal position. This is necessary to maintain the functionality of the seals, which requires them to be in contact with the shock absorber fluid. But during long-term storage of twin-pipe shock absorbers, liquid spontaneously flows from the inner to the outer cylinder, and air penetrates into the freed volume. As a result, the shock absorber itself partially loses its functionality, and after installation on the car it will knock when driving over uneven surfaces, and its throttle valves are subject to destructive loads.

To bring the shock absorber into working condition, it must be pumped before installation. To do this, turn the shock absorber over with the rod down and push the rod in as far as it will go. In this position, you need to pause for 2 - 3 seconds. Then, holding the rod, the shock absorber is turned over with the rod up. Again pause 3 - 6 seconds. Next, the rod is extended to the end of the stroke, the shock absorber is again turned over with the rod down and the procedure is repeated again. A total of 5 - 8 repetitions may be required, after which the air will be forced out of the cavity in which its presence is undesirable, and the shock absorber can be installed on the car. "

Shock absorbers are all divided into two groups: single-tube and double-tube.

Single-pipe ones look something like this:

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There is no need to pump them, because the buffer zone F , filled with high-pressure gas, is separated from the oil working cavity D by a swinging piston E , through which gas cannot leak anywhere.

But if you want to pump it up, then you can do extra work, although this will make the shock absorber neither hot nor cold.

Twin-tube shock absorbers look like this:

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They are available with low-pressure gas pressure and without pressure. Accordingly, oil is pumped into cavity B under low pressure (gas-oil shock absorbers) or simply air is pumped there, as in standard shock absorbers (oil shock absorbers).

Both twin-pipe shock absorbers must be pumped before installation. This is done in order to expel gas or air from the working cavity E , which can get there through valve F , into the buffer cavity C.

A primitive valve design is shown here:

Operating principle

It doesn't matter how the shock absorber is designed. All of them, regardless of type, operate on the same principle

This means that, regardless of type, they need pumping. In the shock absorber chamber, the piston performs a reciprocating movement. The piston has several holes. As the mechanism moves, the pressure in the chamber increases. By the way, it becomes larger when the car moves at low speed.

Important nuances of proper pumping

Currently, an impressive number of different automotive shock absorbers are sold, including:

• Kayaba;
• Monroe;
• Phoenix;
• Demfi;
• Bosch;
• Sachs;
• SS20, installed mainly on VAZ;
• Febi;
• Boge;
• ASM;
• Delphi;
• RTS, etc.

In reality, bleeding shock absorbers yourself is not that difficult. You just need to know about some basic nuances, general recommendations, and also take into account the type of part. Each variety has its own special instructions. You can easily emphasize a lot from the video tutorial on leveling up.

Often, you don’t even need a special tool. The main thing is to have gloves at your disposal to prevent damage to your hands and also to protect yourself from contamination.

As for the general rules, they are approximately the following:

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• After bleeding and immediately until installation, the shock absorber should be kept strictly in a vertical position;
• If you turn the element over, air will get inside again;
• Some shock absorbers require draining the oil;
• The bleeding procedure largely depends on the type of part used;
• The oil can be drained by dropping the piston into the lower part of the structure, without pressing about 30 mm;
• An alternative option is to use a special groove provided by the manufacturer.

In addition to general recommendations, be sure to refer to the instructions that are relevant for a specific type of car shock absorber.

Bleeding rear shock absorbers before installation

Bleeding is an easy procedure; new shock absorbers do not need to be sent to a service center. To properly pump the device, you need to follow this sequence of actions.

1. Install the stand with the stem down. The base must be solid, ideally a concrete floor.
2. Smoothly compress the product.
3. We fix the position for two seconds.
4. To get the rod back, you need to turn the shock absorber over and pull the tube out manually. Usually the rod rises without outside help.
5. Leave the rod in the extended position.
6. We repeat the procedure two or three more times.

After this, the rear struts can be installed on the lever or axle of the car.

Why is pumping done?

Not everyone understands why pumping is done and whether it is necessary at all. Some clarity should be provided on this score in order to finally understand the meaning of pumping and the urgent need for such a procedure.

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The working mechanisms of shock absorbers include special sleeves in their design. If air gets inside them, then the device will not be able to return to its original position. Moreover, before installation, air must be removed from new and old parts if you suddenly bought used shock absorbers because their price turned out to be lower. It cannot be ruled out that during the suspension repair process or during troubleshooting, air penetrated inside the mechanism.

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During storage and transportation, the oil included in the shock absorber penetrates the outer cylinder of the structure, which is why the gas ends up inside the system. This phenomenon leads to the fact that after installing even a new part, a knock is heard.

By performing special actions, excess air is removed from the cylinder. This is done immediately before installation.

And it is still relevant to ask why this is being done. Everything is extremely simple. To ensure correct, efficient and long-term operation of new shock absorbers installed as part of a dependent or independent suspension.

How to work with gas oil

Help: The spelling “gas-oil” is erroneous. That’s right: “gas-oil.”

Gas-oil shock absorbers must also be pumped before installation, whether new or used.

1. The stand must be turned into a vertical position with the cylinder facing up.
2. It is necessary to compress the shock absorber and hold it in this position for several seconds. Hold the shock absorber in the lowered position for several seconds
3. Next, the shock absorber turns over, but must be in a compressed position.
4. The cylinder is pulled out very slowly to its original position. Smoothly pull the cylinder up
5. The procedure should be performed 3-4 times at short time intervals - no more than a few seconds.

After bleeding, do not turn the shock absorber over, otherwise you will need to perform the procedure again. If you hear a slight slurping sound when you press the body, don’t worry. This is not a malfunction.

How to pump such shock absorbers (video)

https://youtube.com/watch?v=-9JfmTW1ldM

If all actions are performed correctly, there should be no knocks or other extraneous sounds. Otherwise, the procedure should be repeated. If you cannot bleed the shock absorber yourself, you should contact a specialized service. There are many devices, stands, attachments and other special equipment for high-quality performance of the procedure.

conclusions

As a result of pumping, the shock absorber receives the necessary functionality. It will work correctly, and the service life will increase by 40% compared to the unpumped version. You should not neglect pumping the gas-filled mechanism, otherwise the upgrade will not live up to your expectations.

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We recommend service station technicians to bleed the shock absorber two to three times before installation. This allows you to identify cases of stuck valve mechanism, as well as other cases of valve mechanism malfunction.

We also draw your attention to the fact that small dips in the resistance of the valve mechanism, as well as the difference in the speed of the rod exit in gas-oil shock absorbers, are not a malfunction and in no way affect the operation of the shock absorber.

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Before installing a twin-tube shock absorber on a car, it must be brought into working condition. During transportation and storage in twin-tube shock absorbers, working fluid can flow from the inner to the outer cylinder, and boost gas or air enters the inner cylinder. In this case, the shock absorber will make knocking noises when operating in the car’s suspension, and its throttle valves will be destroyed. To avoid damage to the shock absorber, it MUST be brought into working condition (pumped) before installation.

All shock absorbers are pumped in the same position in which they are installed on the car, vertically. After pumping, the shock absorber should be in the working position, vertical, until it is completely installed on the car.

Please note that some shock absorbers are equipped with oil drain mechanisms. In some shock absorbers, to drain the oil, the rod is provided to fall into the shock absorber, after which the oil is removed from it. In other shock absorbers, a special technological groove is made at the very top of the rod. Therefore, when bleeding the shock absorber, we recommend not fully compressing the shock absorber. The shock absorber rod should remain 2-3 cm uncompressed (the working surface of the rod should not reach the top of the strut cup by 2-3 cm), and if there are technological grooves, it should be compressed to them.

Based on materials from https://www.kybcom.ru/prokachka.html

Instructions for installing oil and gas-filled shock absorbers

To ensure that your shock absorbers last as long as possible, we recommend following the rules below:

1. Immediately before installing the shock absorber, it must be pumped as follows:

1. turn the shock absorber upside down and wait 3 - 5 seconds;
2. Slowly compress the shock absorber all the way and wait 3-5 seconds;
3. holding the shock absorber in a compressed state, turn it over to the working position and wait 3-5 seconds;
4. after this, let the rod come out (for gas-filled shock absorbers); for oil shock absorbers, it must be pulled out for the entire working stroke
5. procedure 1-4 should be repeated several times until the failure completely disappears when the shock absorber is operating on rebound (point 4).

2. It is necessary to use a special tool to hold the rod from turning to prevent damage to the chrome plating.

To do this, it is prohibited to use pliers, a gas wrench or other tools not intended for these purposes, because worn chrome plating of the rod can lead to disruption of the shock absorber's operating functions.

Soon this defect will lead to wear of the oil seal and rod guide. This, in turn, leads to oil leakage and reduced shock absorber service life.

3. Shock absorbers should only be tightened after the vehicle is on its wheels, or when the wheels are raised with a transmission jack or similar equipment to level the shock absorber mounting locations.

4. It is unacceptable to use pneumatic tools to install shock absorbers. Using such tools may result in the threaded part of the shock absorber rod breaking off.

5. It is necessary to use a torque wrench (wrench with a torque limiter) when tightening threaded connections to maintain the tightening torque; overtightening the nuts and bolts can damage the fasteners and can cause premature failure of the shock absorber.

When operating a car in the winter, after a long period of parking, it is necessary to drive the first 500 meters at a speed of no more than 30 km/h to warm up the oil in the shock absorbers to operating temperature.

based on materials from the site: https://www.4x4sport.ru/publications.html?publications=publications20

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When should you check the shock absorber struts?

The usual problems of this part of the car are familiar to many; the front pair and rear pair of shock absorber struts are checked using these signs:

• Loss of tightness inside the rod seal. This leads to oil leakage from the rack. It starts unexpectedly and is difficult to predict. It can be so serious that the functionality of the unit is completely lost.
• The rod moves too easily inside the pipe. The strut itself was a shock absorber, but becomes a rack for the suspension spring. We need to check the valves, dig, so to speak, inside them.
• Compression of the shock absorber or its rebound is accompanied by excessive swaying of the parts. This occurs due to abrasion of the cylinder wall or rod. The risk is about the same as with broken valves. The unit does not work, it rattles wildly and makes noise. Continuing to drive in such a situation is not only uncomfortable, but also dangerous.
• The shock absorber is somehow damaged externally. There are dents, there may even be cracks inside the eyelet. This affects the entire chassis and provokes more serious problems in the future.

Whatever problem you find: remove the strut, take out the spring. You don’t need a special tool for this, but it’s better to work in the garage. It happens that owners of foreign cars first notice that the struts are leaking and then contact the service center to check the car on a stand.

The design and principle of operation of a car shock absorber

So, what is a shock absorber and what is it for? When driving over bumps, different forces act on the wheels of the car. These forces are transmitted to the car body using springs and a system of suspension arms. A significant part of the forces is absorbed by springs and suspension arms. But every action has a reaction.

For example, a car wheel ran over a bump, the spring compressed (that is, it took the impact and accumulated energy) and you felt almost nothing. But the spring is already compressed and it must deflate, and having done this, it will give off part of the accumulated energy to the car body, simply throwing it up.

Having thrown the body up, the spring is without load and pulls the wheel upward, trying to tear it off the road. This will happen exactly until the moment the car body again begins to put pressure on the spring and, accordingly, on the wheel. At this moment, the wheel practically does not touch the road, and you risk losing control.

The body, having pressed on the spring and pressed the wheel to the road, again compressed the spring, which had accumulated energy, and which in a split second would certainly begin to decompress, and the whole cycle would begin again. And this will continue until the vibrations die out. But as soon as the vibrations die out, another bump in the road will definitely appear and everything will begin with renewed vigor.

In order to prevent rocking of the car body, as well as to prevent the transfer of compression energy from the spring to the car body, shock absorbers are used. These devices do not allow spring vibrations to occur during decompression, and if they do occur, they are quickly damped.

In this article I will not go into ancient times (by automotive standards) and talk about friction-type shock absorbers. I’ll start my story with shock absorbers that are widespread everywhere - these are hydraulic shock absorbers.

Today, two types of hydraulic shock absorbers are used in cars - single-tube and double-tube. Or as they are also popularly called oil, gas-oil and gas. Which is not entirely true, because at the moment there are practically no oil shock absorbers left on the market. The vast majority of modern shock absorbers are gas-oil. And they differ in design - single-pipe and double-pipe. Gas shock absorbers are used under increased loads, for example in motorsports, and are several times more expensive than gas-oil shock absorbers.

So, next we will talk about gas-oil shock absorbers, which we will divide into single-pipe and double-pipe.

What is needed to pump racks correctly

Any shock absorbers need to be pumped:

• front and rear,
• new and contract,
• one- and two-pipe,
• collapsible and non-collapsible.

The pumping process is not difficult. No special tools required. Just gloves will be enough to protect your hands from injuries and dirt. First, you should familiarize yourself with the general rules for its implementation:

• after completing the procedure, until the very moment of installation in its place, it is necessary to keep the part vertically - otherwise air may again get into it;
• It is important to consider the need to drain oil from some shock absorbers.

Shock absorbers can be either single- or double-tube, and there are also struts with a remote chamber.
Draining can be done in different ways:

• by sinking the piston into the lower component of the part (there should be an undercompression of approximately 3 cm);
• through a groove designed for this purpose - it is usually present in the upper part of the part.

Tips for replacing shock absorbers

However, shock absorber manufacturers offer a number of tips to help you replace them correctly and quickly. For example, the manufacturers of KYB and Kayaba recommend adhering to the following recommendations:

• When bleeding the shock absorber, do not use any additional tools to hold the rod in order to avoid damage to the seal and possible premature leakage of fluid;
• do not use pneumatic tools to tighten the rod nut;
• It is highly undesirable to use old boots when replacing the original shock absorber,
• gaskets and shape washers;
• shock absorbers should only be installed in pairs;
• Before fixing the upper mounts, you must make sure that the car rests freely on four wheels and all jacks and stands have been removed.

Thus, it is necessary to prepare the shock absorber for use when replacing it, and if you take into account the manufacturer’s recommendations, the unit will last a long time and without problems. Smooth roads to all!

Replacing the rod, valves, adjusting the stiffness of shock absorbers

The next malfunction is damage to the rod, seals, and valves inside the strut. There is a certain selection of spare parts on the market for repairing dismountable shock absorbers. In addition, an experienced car enthusiast never throws away old spare parts, but tries to repair them. In addition, you can always extract workable parts from them.

So, let's disassemble the shock absorber.

Don't forget to wear gloves, the job is dusty

Turning work is usually cheaper than the cost of a new shock absorber

Tip: The entire process of disassembling the shock absorber should be photographed. This will avoid problems during assembly.

Get rid of stains, dirt and dust while disassembling

All parts must be carefully checked

It is recommended to replace the oil seal

After pumping the oil, the rack needs to be pumped as usual

Video: How to repair car MacPherson struts

If you have basic information about how your shock absorbers work, you can save money on replacing them. Most rack models are repairable, and components are either purchased at reasonable prices or made independently.

Source

How to bleed racks before installation - step-by-step instructions

Today there are the following types of shock absorbers:

• gas (most often using nitrogen);
• oil;
• gas-oil.

The process of performing a procedure of this type for each variety is associated with some significant features. Familiarization with them is mandatory. If mistakes are made, the working part will quickly fail during intensive use of the car, which threatens early repairs.

Before we get started, I advise you to read our recent article, which discussed the front shock absorber struts. I'll leave the link here. Go ahead, read, get new useful information.

Pumping is considered a key condition for proper installation and further effective operation of the unit. If you do not do this, the part will fail. Moreover, such a malfunction does not fall under the terms of the warranty case. Everything will have to be corrected at your own expense.

The condition of roads in the post-Soviet space is far from the best. This is confirmed by the need to regularly replace shock absorbers on cars. If the operation is carried out at a service station, then there are no problems with this. For those who decide to carry out repairs themselves, you need to know how to perform this operation correctly.

Varieties If a car enthusiast knows what shock absorbers he knows, then we will get something like this: oil, gas-oil and gas. This answer is partially correct. It is more correct to divide into two types: oil and gas. This division is based on the use of different working substances.

Gas shock absorbers use an inert gas, most often nitrogen, pumped under high pressure. In oil shock absorber struts, hydraulic oil and air or gas are pumped into the working space. Structurally, they are divided into two types: two-pipe and single-pipe. The first type of shock-absorbing struts is the most common due to its simplicity and low cost of manufacture.

Oil or gas and oil are used as the working substance. The main disadvantage of oil shock absorbers is poor cooling of the working substance. The oil gets very hot due to its small working volume. High temperatures cause the oil to foam and the shock absorber stops working correctly.

Wait 3–5 seconds. 3. Turn the shock absorber over. Wait 3-5 seconds.4. Extend the rod smoothly to 3/4 of the length. Wait a couple of seconds.5. Turn the shock absorber over and press the rod in again.6. Repeat steps 2–5 from three to six times. After the third swing, check. In this case, you need to sharply press the rod several times - it should move smoothly without jerking.

How to change the rod, valves, how to adjust the stiffness of shock absorbers.

Another problem is a violation of the integrity of the rod, seals, and valves inside the strut. But of course, stores already have a set of spare parts for this unit. And an experienced driver is not in a hurry to take old parts to a landfill; he repairs them. At least some useful details can be extracted.

Replacing a strut or shock absorber from a work point of view is not a very expensive event, even on fairly expensive cars, because it is a simple matter. But when it comes to the cost of a part, the overall repair begins to take on new colors, and the more expensive the car, the darker the shades. Take, for example, luxury crossovers - MB GL500 or BMW X5, for which the cost of one electronically controlled shock absorber strut can reach 1,500 euros. The price for work simply pales against this background. And remembering the main rule of the pendant - if you change it on the left, replace it on the right - you can get an instantly formed gray strand. Today we'll talk about the possibility of getting by with less blood and gray hair - shock absorber repair and why it is sometimes better than new "originals".

Of course, a sharp-tongued reader will say: someone who buys a car for several million can easily spend a hundred or two on racks. This is, of course, true, but only at first glance. Firstly, consider the quality of the road surface, which is far from desired, and imagine how quickly new shock absorbers installed on a car weighing more than 2.5 tons will die. Secondly, one should not discount the fact that people driving a GL500 have the ability to calculate expenses. And at the end of the virtual tour, imagine that you, the owner of the X5, are told: “Repairing one shock absorber will cost you 350 euros.” Almost 5 times cheaper! And what will be your decision after this?

We won’t talk about the design of shock absorbers: enough was said in the article about replacing struts . Today we will focus exclusively on breakdowns and their elimination.

Breakdowns

One of the most common shock absorber malfunctions is leakage of working fluid through a damaged oil seal. There are several reasons why it comes to an end, and the main one is friction. The simplest option is when the service life has expired and the sealing part has worn out. But it happens that the shock absorber begins to “sweat” or leak before reaching half of its service life.

The reason for this may be winter - or rather, frost . For example, you drove out of a warm garage somewhere, stopped to drink hot chocolate and sat for a while in a coffee shop. Due to heating and subsequent sharp cooling in the cold, grains of ice formed on the shock absorber rod. They will tear the seal on a relatively new shock absorber. In addition, death of the seal can also occur after dust and dirt get on the rod due to damage to the boot.

The rod itself is difficult to “kill,” but it moves in the guide sleeve, into which Teflon rings are, in turn, pressed. These rings, of course, wear out, and then the rod begins to experience shock loads in the contact surface. If you do not pay attention to this in time, you can break the entire guide sleeve - and this is already a disaster from the point of view of driving safety. Well, there’s nothing to say about the shock absorber bushings; they can break first. Replacing them is not a big problem, but it happens that this is simply not provided for structurally.

Piston valves are perhaps the most durable elements of the assembly: there is essentially nothing to break in them. But it happens that small particles of dirt get inside the shock absorber through a damaged oil seal and broken Teflon rings. So they can cause a number of troubles, the saddest of which is a loose valve fit. Then the shock absorber will “dangle” during the compression or rebound stroke - depending on your luck.

Gas or air that has gotten inside the shock absorber can also be a problem. This manifests itself in audible shocks from the shock absorber during its operation. The impact occurs when an air bubble passes through the valve and piston, causing the strut to suddenly sag.

How can air get into a monotube shock absorber? Yes, very simply - through a worn out sealing ring of the separating piston. It wears out gradually, so at a certain point it begins to “poison” the gas into the cavity with the working fluid. If problems with tightness are not identified in time, then regardless of whether you have a double- or single-tube shock absorber, foaming of the working fluid will occur with a loss of damping properties and a sharp increase in wear of the rubbing surfaces. If the shock absorber is double-pipe, then due to wear or, again, the ingress of foreign particles, the bottom valve responsible for the compression stroke fails.

With the piston, everything is simple: the sealing ring is more likely to wear out than the piston itself. But for the sake of truth, it is worth saying that there are “craftsmen” in our open spaces who “put this part on both shoulder blades.” The cylinder also rarely attracts attention, and the only thing that can make you sad is scuffing due to the same dirt.

In the case of electronically controlled shock absorbers, in addition to purely mechanical damage, problems arise with the rebound and compression bypass solenoids. If one of them jams, for example, in the open position, it will make the suspension very soft in only one direction.

Diagnostics

Every car enthusiast knows: if you rock the car and it oscillates, as if on waves, it is clear that not everything is in order with the shock absorbers. Leaks of working fluid also quickly reveal at least wear of the oil seal. But if suddenly the rocking of the car does not provide any understanding of the problem, and the behavior of the car in motion is noticeably different from normal, a special diagnostic stand can come to the rescue. There are many of them on the market - for example, we used Emmetec.

The shock absorber is fixed in the stand: the body - in the moving part, the rod - to the plate with a strain gauge. The stand simulates the operation of a shock absorber, moving it either slowly or quickly. Thanks to the sensor, a graph of shock absorber stiffness is drawn during rebound and compression strokes in different operating modes. The master knows what the graph should look like, and if, instead of smooth curves, he suddenly sees any jumps or sharp transitions, he will give an approximate, but more specific conclusion about the technical condition of the “shock.”

Varieties

If a car enthusiast knows what shock absorbers he knows, then we will get something like this: oil, gas-oil and gas. This answer is partially correct. It is more correct to divide into two types: oil and gas.

This division is based on the use of different working substances. Gas shock absorbers use an inert gas, most often nitrogen, pumped under high pressure. In oil shock absorber struts, hydraulic oil and air or gas are pumped into the working space.

Structurally, they are divided into two types: two-pipe and single-pipe.

The first type of shock-absorbing struts is the most common due to its simplicity and low cost of manufacture. Oil or gas and oil are used as the working substance. The main disadvantage of oil shock absorbers is poor cooling of the working substance. The oil gets very hot due to its small working volume. High temperatures cause the oil to foam and the shock absorber stops working correctly.

Shock absorbers are structurally made into two-pipe and single-pipe. Oil and gas are pumped into the middle

Gas-oil shock absorber struts are partially free of this drawback. Oil and air are pumped into a two-pipe housing under a pressure of 2–3 atmospheres. Sometimes nitrogen is used instead of air. This solution reduces the likelihood of aeration - foaming of the oil.

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Structurally, monotube shock absorbers do not have a working chamber. It is replaced by the rack housing. The tube is divided into two sections. The upper part is filled with oil, and the lower part is filled with high pressure gas. There is a valve between the sections.

Gas shock absorbers are of particular interest to drivers. This is no accident. Gas struts are primarily used in motorsports. For sports driving, this type of rack is most often chosen. The operation of the gas shock absorber is ensured by pumped gas under high pressure. Such racks are the toughest and driving on city roads is accompanied by shocks and impacts. Such a ride cannot be called comfortable, but driving will be clear and controlled. Therefore, gas shock absorber struts are used mainly on racing cars.

A special type of shock absorbers are the so-called “reversals”. They were given this name not because they can be placed upside down. In such racks, the reverse position of the rod is used. In conventional shock absorbers, the rod is directed upward. In inversions, the rod is directed downwards and is attached to the shock-absorbing strut body. There is a pseudo-rod on top. It looks much thicker. The operation of the inverted shock absorber is ensured by several plain bearings. This design reduces the vertical and lateral load on the rack.

Bleeding the shock absorber

1. We completely disassemble the rack and clean it. We determine the condition of the rubber seals. Remove jet contaminants and dust from parts.
2. The assembled rod is immersed in oil in a pipe (check what exactly the composition of the liquid should be based on the characteristics of the shock absorber). Our next task is to remove all air bubbles. The shock absorber should be positioned vertically and the oil should be drawn in using smooth movements. The procedure will need to be done several times. You do not need any special devices to repair oil struts.

On non-removable racks, a bleeder fitting is installed in their lower part. A hole is drilled, with its help the rack is filled with oil, the hole is welded. By the way, those who own Russian cars with high mileage follow this path.

Must know

During the pumping process, you must know the following rules:

— Any rack is pumped vertically (the rod should point upward);

— After pumping, you cannot change the position of the stand until it is

installation completed;

— There are shock absorbers whose design allows oil to be drained from the inner sleeve.

This is done like this: the shock absorber rod is pushed inward using a technological groove. It can be seen at the top of the stem.

The most common faults

Among the most popular malfunctions are:

• Fluid leaks;
• Deformations and mechanical damage to the housing;
• Damage to the rod or piston;
• The oil is inappropriate or of poor quality.

Leaks can occur due to wear of oil seals or other seals. Oil seals also wear out naturally - the rod is constantly moving, so the edge of the oil seal wears out after some time. However, most often the oil seal gets damaged due to corrosion, scuffing and dust, sand on the rod.

Deformation of the housing is usually caused by impacts on the housing of the damping device. Dents do not allow the rod to move normally to its full height and in the place where there is deformation, the piston can rest.

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The piston can be damaged only in one case - if the car falls into a hole at speed. The damper cannot withstand it and breaks through. At the moment of breakdown, the piston collides with the bottom of the chamber, which causes damage to the piston. As a result, the valves are also damaged, and the processes of oil flow from chamber to chamber are seriously disrupted.

Oil is the working fluid in a car shock absorber. The operation of the damper depends entirely on its characteristics and quality. If the oil has a low viscosity, then there will not be the required resistance to the movement of the piston - the damper will “break through” even on small bumps. In winter, oil with a higher viscosity will create too much resistance.

How to properly check shock absorbers on and off the road

You can determine whether the damper is working properly by its appearance. If traces of oil are visible on the body, this indicates a violation of the tightness of the chambers due to wear of the oil seals or seals. The properties of such a damper will be below normal or will not exist at all.

The body is also inspected for deformations - even a slight dent can lead to difficulty moving the piston and to complete jamming.

Fasteners must be intact and not damaged by corrosion. The rubber bushings installed in the lower hinge must also be intact and have no signs of destruction.

The damper rod must have a perfect mirror surface. If there is no mirror, then the piston has no movement and the shock absorber does not perform its function.

If the shock absorber has already been removed, then to check it, install it vertically. The bottom bracket is fixed with your feet, and the rod is pulled out with your hands and released. If the shock absorber is working properly, then the resistance to the upward movement of the rod should be much greater than the resistance when the rod moves down.

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If the rod moves both down and up with the same force, then there is little or no oil in the cylinders. If the resistance decreases in the extreme positions of the rod, then this indicates air in the chamber cylinder.

You can check the operation of the shock absorbers on the car. To do this, swing the car by the front and then by the back. If the damper is working properly, the car will swing once. If the rack is jammed, you won't be able to rock the car.

Which oil shock absorbers are better?

1. KONI are the most expensive shock absorbers, but also the most durable. These racks are the development of the Dutch company of the same name. They are used on virtually all types of transport. They are distinguished by the ability to adjust characteristics.

2. Bilstein is a symbol of reliability and quality. They are quite common. Installed on the following car brands: Ferrari, Jaguar, Lamborghini.
3. Boge - produced by a well-known company from Germany. Supplied for installation on cars of the following concerns: Volkswagen, Audi, BMW, Alfa Romeo, Volvo. They are affordable and do not actually change the suspension characteristics of modern foreign cars.
4. Monroe is one of the best American companies. Its products are installed on new vehicles in America and throughout Europe. One of the best developments is the Reflex series shock absorbers, which are able to provide maximum contact with the road surface.

5. Tokiko is one of the largest stand manufacturers in Japan. The reasons for the popularity of these products are low price, high quality and long service life. However, when purchasing these products, beware of Chinese counterfeits.
6. Sachs - these products are manufactured by a German company. As it should be, all products are reliable and high quality.
7. Kayaba, a Japanese company that manufactures these products, appeared on the market in 2000 and almost immediately gained wide popularity. The company's main advantages are good quality, a wide range of products and low cost. Kayaba supplies its products to Mazda, Toyota and Honda.