DIY pneumatic bellows repair

Most modern business class cars have air suspension. It provides additional comfort and allows you to control the clearance height, and also increases the level of safety of the machine.

The principle of operation of the device is as follows: the electronic system raises and lowers the car by adjusting the pressure in the air bellows.

The main components of the air suspension are:

• pneumatic cylinders, which serve as shock absorbers in this design;
• a central receiver, necessary for supplying air to the above element;
• a compressor forcing air into the receiver;
• valve block and sensor sensors, the task of which is to monitor the traffic situation.

But one day, one of these elements may fail. The owner of a car with air suspension most often faces the following problems:

• rupture of the air spring chamber;
• air suspension compressor failure;
• damage to the stiffness valve of the pneumatic strut;
• loss of tightness with front air struts.

Diagnostics and solutions to these problems are the main task of our specialists.

If suddenly your favorite car begins to lean on its side or falls below the permissible level - your friend urgently needs the restoration of pneumatic bellows.

Our company is engaged in the restoration of pneumatic bellows on the Audi Allroad and Honda Element car models. And has more than five years of experience in the European market. The main specialization of the company is the restoration of air bellows and the repair of air suspension compressors.

Original sleeves often require replacement after two years. Their damage occurs due to the reagents that are sprinkled on the road, rubber is destroyed at the place of the folds, and then the cord deteriorates. Sealing damaged sleeves with sealants is a very dangerous method, as it can lead to an explosion of the cylinder. And the ingress of sealant into the pneumatic system can damage the valve. And not tight pressing of the sleeve to the flange leads to its slipping off the cylinder.

Buying new original spare parts will cost much more than repairing air bellows. At its core, repair is the replacement of an old pneumatic arm with a new one. The air hose has three layers of rubber and two layers of high-strength cord, which is made by winding the thread on a special machine. In this case, there are no butt joints between the layers. Our company can offer its clients:

• high quality raw materials;
• sleeves are of European production.

The quality of work on the restoration of pneumatic springs has no complaints from the company's clients. After all, our material surpasses the original parts in terms of wear resistance, thanks to its unique rubber with a high rubber content. Allowing for increased elasticity, its temperature range is probably not wide from -60 to -110 degrees Celsius. It is logical that the parts are more durable than their counterparts.

In addition, a stainless steel guide glass is installed on the pneumatic bellows, and a cuff closes its working part, which does not allow external negative factors to influence the element. When carrying out the restoration of pneumatic bellows, it is replaced with a new one, made in accordance with all the required standards from material of European quality.

An additional plus for our clients will be a one-year guarantee for the work done, without limiting the car's mileage.

Anaerobic sealant "SantechMaster Gel" is intended for sealing metal and flange joints. It is not recommended to use for other materials, because there is no 100% guarantee of reliability.

However, the practice of working with gel on plastic surfaces is already available from several customers.Still, we strongly advise you to follow the instructions.

Many modern vehicles use an air suspension system. The executive element of the system is a pneumocylinder. Like any car part, it can fail. For example, let the air pass through the connection point.

It is not difficult to identify this. An air leak is diagnosed with any foamy liquid - bubbles will appear at the leak.

SantechMasterGel is used to secure the fitting to the pneumatic bellows and seal the connection. It is necessary to apply a small amount of sealant to the threads of the fitting and to the threads in the cylinder bore. Then collect the connection and leave for half an hour. Then pressurize the system with air to check for leaks.

Because The air spring is made of plastic, the fitting point of the fitting often breaks, so it starts to poison the air. SantechMasterGel will help you avoid regular repairs and waste of money.

In pursuit of excellence, you choose the best. AS8 Club - those who have made their choice.

Message rjcnz_66 09-03-08, 09:10 Tue Oct 06, 2009

Message rjcnz_66 09-03-08, 09:10

Message rjcnz_66 09-03-08, 09:10

Message rjcnz_66 09-03-08, 09:19

Message rjcnz_66 09-03-08, 09:23

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Message vovvw Wed Oct 07, 2009 7:18 am

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Message dasus »Wed Oct 07, 2009 9:00 am

Bone question is one: where was the poison in the area of ​​the air bag?

Message rjcnz_66 Wed Oct 07, 2009 9:41 am

Message rjcnz_66 Wed Oct 07, 2009 10:47 am

Message rjcnz_66 »Wed Oct 07, 2009 11:00 am

Message Akin Wed Oct 07, 2009 11:06 am

Welcome to the Audi Allroad Owners Club.

Repair of air suspension (restoration of tightness of air bellows) AUDI ALLROAD!

Here, for all owners of the first generation Allroad, a solution to the sore problem of "current" air bellows is offered by sealing using a unique technology with full restoration of their performance for a long service life.
The technology developed by us is quite simple and at the same time effective, therefore in especially difficult cases (when the machine lies on the bumpers and does not rise in any way due to the ruined compressor) we make a visit to the customer.

Part 1 In the course of long research, we have determined the exact place of the leakage of the allroad pneumatic bellows. When the suspension is transferred from the second to the third position, the cuff begins to roll out along the piston, moving from a smaller diameter to a larger one. The inner layer of the balloon's rubber undergoes strong tensile deformations. This is how horizontal cracks in the inner layer of the cylinder appear, which are the cause of air leakage. At the same time, the double cord of the cylinder retains its performance characteristics.

1. Scheme 2. Photo of the wrong side of the air spring cuff

As proof of this theory, you can study the reviews of the owners of Volkswagen Touareg cars, produced since 2002, on which second-generation air bellows are installed, which have gotten rid of our problems.
I would like to note that replacing the pneumatic balloon is not a panacea, since the new balloon starts to "leak" almost immediately, which we installed on several machines. Perhaps this is due to our difficult road conditions and the driver's confidence that he has a full-fledged jeep at his disposal. Of course, the air leak is initially small and usually not noticed by the owner, but the fact remains: if a crack has appeared, then in the future it will only expand, which will eventually lead to the repeated replacement of pneumatic elements and, also, to premature compressor wear.

Photo of the new rear left cylinder, which has passed only 10 thousand km. after installation

Based on the foregoing, we have developed a technology for restoring the tightness of "current" pneumatic cylinders without dismantling them from the car, which is also preventive and is recommended for use on new, newly installed cylinders.
The essence of the technology boils down to pouring a special sealant that does not lose its properties into the fold of the air bellows cuff.This sealant is in a liquid state in a wide temperature range for about 5 years and instantly stops air leakage through cracks, and also prevents the appearance of new ones, being a rubber conditioner, i.e. restores and maintains its elastic properties.

The composition of the sealant, its dosage and the method of pouring is our know-how, but this work is backed by our six-month warranty. The warranty is provided for the complete elimination of the defect described above. The warranty does not cover damage to the outer rubber layer and cord breakage.

P.S. Bringing pneuma to this state is dangerous:

This is fraught with an explosion of the balloon and loss of control over control.

The most frequently asked questions and answers to them:

Question: What is the most simple and effective way to check the pneumatic system for leaks?
Answer: It is enough to put the 2nd level of the suspension and pull out the fuse No. 17 at 10A - the system will turn off. In this case, all valves will be closed, the control logic will not work. Next, you should drive a car for 3, 4 days, carefully observing the change in ground clearance: if the car is skewed to either side, then that pneumatic element is leaking. Possible daily amount of suspension level **** due to the difference between day and night temperatures.
WARNING: this fuse also disables some car systems such as navigation.

The air suspension of AUDI-ALLROAD produced in 2000-2005 is rightfully considered the most unreliable system of this car, and this is not without reason: it uses first generation air springs as elastic elements, which have a number of annoying technical omissions. Firstly, this is the absence of an external rigid guide that protects the cuff under pressure from excessive tensile deformations. Secondly, this is the absence of an anther that protects the cuff from an aggressive external environment. True, at the end of 2007, a new revision of pneumatic cylinders was released, but, unfortunately, their quality has deteriorated greatly compared to those that were installed on the car at the factory, and now the new original cylinders are barely enough for a mileage of 15-20 thousand km.
As a result, each allroad owner sooner or later encounters the problem of leakage of pneumatic elements and is faced with the need for their expensive replacement.

What is the benefit of installing external rails on our air bellows?

First, the guides relieve excessive stress on the bellows cords, thereby preventing excessive stretching of the rubber in the cracked area causing the bellows to leak.

Secondly, they completely eliminate the contact of the working surface of the air spring with dirt and sand flying from under the wheels.

Thirdly, the car with the guides installed becomes more collected when driving and does not fall when cornering. At the same time, the comfort of the car remains at the same level.

... Do not be afraid of perfection, you will never achieve it.
... Salvador Dali

but since it helps, you need to go to the knowledge base

everything is bullshit, except for gifts, but if the gift is bullshit.

everything is bullshit, except for gifts, but if the gift is bullshit.

The fact that the plate helps to put the pillow in place is a fact, but it seems to me that it also supports the pillow itself. Indeed, most of the time, the pillow is in tension, under load, so the upper pin will not fall out of the frame, but sometimes it happens that the wheel hangs out completely and this is where this plate helps.

everything is bullshit, except for gifts, but if the gift is bullshit.

Often, in conversations of experienced truckers, one can hear a discussion of the topic of fines for exceeding the dimensions in height, as well as for overloading. In this case, one of the reasons for such incidents is a faulty condition or incorrectly adjusted air suspension of the truck.Let's consider in more detail the principles of operation of the main elements of this suspension, as well as some of the features of its adjustment.

The air suspension of a truck allows not only to achieve a smoother running of the road train, but also, in contrast to the spring suspension, makes it possible to adjust the height of its frame, which plays an important role in coupling and uncoupling, loading and unloading, as well as passing weight and size control.

Modern pneumatic systems on trucks are traditionally divided into several basic types, depending on the way they are operated. The first is completely electronic, such as are usually installed by concerns - truck manufacturers MAN, Mercedes, DAF, Renault, Scania. The second is electromechanical, on trucks Scania, Volvo. The third type is mechanical control, such systems are mainly used on older models of tractors and on the suspension of trailers. Briefly about each of them.

As conceived by the engineers, after the contours of the working and parking braking systems are filled, air enters the air suspension of the truck. A prerequisite for this is the presence of two bypass valves in the air suspension. One of them (unidirectional, that is, without a reverse flow) passes air to the pillows after reaching a pressure in the system of about 8 atmospheres. The second, on the basis of the reverse flow principle, gives the air a path from the pillows to the air suspension receiver after reaching the pressure level of 10 atmospheres. Thus, this valve allows using the air supply in the receiver in the opposite direction.

In the case of mechanical or electromechanical suspension, air enters initially at the valve inlet of the truck frame level. This device is located on the frame and is connected to the axle by means of hinges and an adjustable link. This is necessary so that the suspension automatically corrects movement in the transport position, and also performs the function of an automatic height limiter at maximum lift. The valve can perform several "operations" depending on how the truck frame is positioned. In relation to the axle: allow air to pass to the cushions, block the air path or partially release air, connecting the air bellows to the atmosphere. 2 valves can be installed on the rear axle, which makes it possible to regulate the right and left sides separately from each other. Each terminal has its own designation, for example, inlet 11, atmosphere 3, etc. An example of an application for such a valve is the mechanical air suspension of a Scania truck.

A manual level control valve is installed between the air bags and the valve. It can be either mechanical (assumes the presence of a shift lever) or electro-pneumatic, controlled from the truck cab using a remote control. Typically, this crane has several positions. First, transport - air bags are connected to the floor level valve. Secondly, the lifting of the body - the air bags are connected to the air receiver. Thirdly, the lowering of the truck body - air from the pillows is released into the atmosphere. With mechanical control of the crane, the handle has one more position - intermediate or STOP, while the leads from the pneumatic bellows overlap. The device for a manual crane is quite simple. By the way, nowadays they are very rare on trucks, mainly on older models, which cannot be said for trailers with air suspension, which are equipped with such a crane as standard.

An electro-pneumatic crane is installed on more modern truck models and its device is, of course, more complex than a mechanical one. Combinations of 2 solenoid valves perform the functions of transport position, lifting and lowering. In this case, a lift height limiter in the form of an inductive sensor is installed on the truck frame.If there is air suspension on the front axle, then it is controlled by a separate electro-pneumatic valve.

The system is presented slightly differently on Scania trucks. The control is carried out using three valves, each of which performs the functions of lifting, air release, etc.

Let us briefly consider the features of the air suspension of a truck equipped with a 6 x 2 wheel arrangement. Its structure is complicated by the presence of an additional axle, the so-called "sloth". It can be located both in front of the driving axle and behind it. During normal, trouble-free operation of the system, the air pressure in the pneumatic hoses of the supporting and driving axles of the truck is the same. This makes it possible to equally distribute the axle load and thus comply with legal regulations.

Often, the supporting auxiliary axle of the truck is made lifting. This reduces rolling resistance and tire wear. In practice, it looks like this. A solenoid valve installed in the pneumatic line stops the air supply to the air bags and at the same time releases the air accumulated in them into the atmosphere. At the same time, air is supplied to the cushion designed to lift the truck axle. In order to avoid sagging of the suspension due to an increase in the load on the drive axle, pneumatic cylinders of the floor level valve system are required. They make it possible to maintain the transport position in the suspension by lengthening the thrust connecting the valve with the main axle. The amount of cushion pressure indicates axial load. The designers have developed the system in such a way that it automatically detects and reacts to the overload on the drive axle of the truck. For this, a sensor is traditionally installed in the 6 x 2 suspension in the form of a conventional contact, which is triggered when the maximum load is reached, while the axle is automatically lowered.

Now a little about malfunctions. The frame level traction valve joints will wear out over time and may come off. The truck in such a situation may decrease or "grow". In order to avoid this, it is advisable to change the hinges in time, while maintaining the original length of the rod. If the suspension of the truck cannot be adjusted, and the thrust is in place, you should pay attention to the frame level valve. Usually, this problem can be easily repaired if a dedicated truck repair kit is available. The only contraindication in this case is a malfunction of the eccentric or lever shaft. An electro-pneumatic crane on a commercial vehicle is also repairable with an appropriate repair kit. Before that, it is necessary to check the solenoid windings with an ohmmeter. In some cases, on VolvoFH trucks, you can face a problem when there are different pressures in the cushions. Moreover, if 2 level valves are installed, which is a rarity, then the reason is in their different work. However, most often 1 valve is installed on both sides and, most likely, the reason for the different pressure in the cushions must be sought in the electro-pneumatic valve of the truck.

Modern truck manufacturers in most cases equip the air suspension with an electronic control system. Officially, the system is designated by the abbreviation ECAS, which stands for ElectronicallyControlledAirSuspension. Different manufacturers may call it differently, but the meaning and principle of its operation remains the same. Two sensors are installed on the truck frame, which are the measuring part of the electric air suspension of the truck. If there are air bags on the front axle, only one sensor is installed. The sensor device is simple and includes a core and a coil. The first moves inside under the action of a special lever.Depending on its position, the coil has a different inductance. This value, in turn, transmits information about the current position and height of the suspension to the electronics. The most important part of the electronic system is the control unit, located for convenience in the cab of the truck. It consists of a memory block, a microprocessor and an output stage that allows you to control the executive elements.

In our case, the main element is the solenoid valve block located near the air bellows. When driving one axis, it has 3 magnets. Each of them performs its own function, which allows you to adjust the height of the sides and maintain the horizontal position of the truck.

The suspension control panel is an integral part of the system. It fulfills both the traditional functions of transport position, lifting and lowering, and can be programmed to implement some intermediate positions. This is convenient when it is necessary to move an unloaded truck, since lowering the level of the transport position makes it possible to reduce tire deformation.

The instrument panel of the system control panel is equipped with indicator lamps that indicate ECAS operation. So, for example, a yellow lamp means that the manual adjustment mode is activated (when set to transport position, it goes out), as well as the lifting of the supporting axle of the truck. The red color of the lamp traditionally indicates a system malfunction. To determine the breakdown, you must connect a special diagnostic tester. Due to the fact that the interconnection of elements is carried out in a digital format, one cannot do without special devices and skills. Therefore, let's try to understand some of the features and types of truck malfunctions.

Conclusion I would like to draw your attention to a few expert advice. Firstly, if you connect a pressure gauge to the control outlet of the springs, it will accurately show the axle load of the truck with the load. Secondly, different pressure in the air springs of the main and trailing axles can distribute the axle load unevenly. Third, correct axle load distribution is not a direct consequence of good frame height adjustment of the truck.

Most modern business class cars have air suspension. It provides additional comfort and allows you to control the clearance height, and also increases the level of safety of the machine.

The principle of operation of the device is as follows: the electronic system raises and lowers the car by adjusting the pressure in the air bellows.

The main components of the air suspension are:

• pneumatic cylinders, which serve as shock absorbers in this design;
• a central receiver, necessary for supplying air to the above element;
• a compressor forcing air into the receiver;
• valve block and sensor sensors, the task of which is to monitor the traffic situation.

But one day, one of these elements may fail. The owner of a car with air suspension most often faces the following problems:

• rupture of the air spring chamber;
• air suspension compressor failure;
• damage to the stiffness valve of the pneumatic strut;
• loss of tightness with front air struts.

Diagnostics and solutions to these problems are the main task of our specialists.

If suddenly your favorite car begins to lean on its side or falls below the permissible level - your friend urgently needs the restoration of pneumatic bellows.

Our company is engaged in the restoration of pneumatic bellows on the Audi Allroad and Honda Element car models. And has more than five years of experience in the European market. The main specialization of the company is the restoration of air bellows and the repair of air suspension compressors.

Original sleeves often require replacement after two years. Their damage occurs due to the reagents that are sprinkled on the road, rubber is destroyed at the place of the folds, and then the cord deteriorates.Sealing damaged sleeves with sealants is a very dangerous method, as it can lead to an explosion of the cylinder. And the ingress of sealant into the pneumatic system can damage the valve. And not tight pressing of the sleeve to the flange leads to its slipping off the cylinder.

Buying new original spare parts will cost much more than repairing air bellows. At its core, repair is the replacement of an old pneumatic arm with a new one. The air hose has three layers of rubber and two layers of high-strength cord, which is made by winding the thread on a special machine. In this case, there are no butt joints between the layers. Our company can offer its clients:

• high quality raw materials;
• sleeves are of European production.

The quality of work on the restoration of pneumatic springs has no complaints from the company's clients. After all, our material surpasses the original parts in terms of wear resistance, thanks to its unique rubber with a high rubber content. Allowing for increased elasticity, its temperature range is probably not wide from -60 to -110 degrees Celsius. It is logical that the parts are more durable than their counterparts.

In addition, a stainless steel guide glass is installed on the pneumatic bellows, and a cuff closes its working part, which does not allow external negative factors to influence the element. When carrying out the restoration of pneumatic bellows, it is replaced with a new one, made in accordance with all the required standards from material of European quality.

An additional plus for our clients will be a one-year guarantee for the work done, without limiting the car's mileage.

Malfunctions in the operation of the air suspension compressor occur due to:

1. wear of parts of the piston group;
2. failure of the electrical part of the compressor (electric motor);
3. depressurization of the pneumatic cylinder, which leads to a drop in pressure in the system, and, as a result, increases the load on the compressor.

Therefore, compressor repairs may include:

1. replacement of the piston ring and sealing rubber bands;
2. replacement of the air dryer, mechanical and electromagnetic valve, air duct, piston sleeve;
3. replacement of the electric motor.

If the air spring is damaged, it must be replaced.

After performing the necessary replacements, the compressor is diagnosed and brought up to operating characteristics - pressure 8-10 or 18-20 atm, depending on the type of compressor.

During the repair, only new original spare parts are used.

We repair the temperature sensors of the G290 air suspension compressor. These types of sensors are installed on the following car models: Audi, VW, Porsche.

At present, the situation on the market for original spare parts has developed in such a way that for many car models there are no spare parts for air suspension repair in the warehouses of suppliers of spare parts for repairing air suspension. Delivery on order is possible, while the terms are 15 days - at best, more often - 30-40 days. This is understandable, because the price, for example, of a strut (a shock absorber with an air spring installed on it) is more than 1,000 euros.

What to do when repairs are needed as soon as possible?

• You can try to find a used spare part, but there is a high probability of buying a pig in a poke, because visual inspection does not make it possible to assess the serviceability of the shock absorber and the tightness of the air spring.
• You can repair a damaged cylinder on your own, using glue and sealants, but, as practice shows, this will only prolong the agony for several days. Moreover, during this time, the sealant can get into the system and create an additional load on the compressor and other elements of the system.
• Or you can turn to specialists for repairs, and get a 2-year warranty for the work performed!

Pnevma, having examined the design of the air elements of most car models equipped with air suspension, performs repairs only when repair will be really high quality and will give a guaranteed positive result!

What causes the air struts to fail?

First of all, this is the wear of the rubber sleeve of the air spring. The resource averages about 100,000 km of run, but exposure to road reagents, mud, as well as difficult climatic conditions can significantly reduce their service life.

Secondly, these are leaking shock absorbers. In this case, the air spring itself may remain intact; when replacing the shock absorber, it will be necessary to replace the O-rings, which will be damaged by escaping oil.

How we carry out repairs:

• We carry out a complete troubleshooting of a damaged air spring or air suspension: check for leaks, check all sealing connections, check the shock absorber.

• The damaged elements are being replaced.
• When replacing the air bellows sleeve, reinforced rubber with improved characteristics and at the same time structurally identical to the original (thickness, geometric dimensions) from Continental, ATE, Vibracoustic is used.



• For crimping rubber hoses, seamless rings are used, which have undergone nickel-plating to exclude corrosion; in width and thickness, they are also identical to the original.

• We make replacement of failed or partially lost their properties of sealing elements, fittings, valves.
• We use professional crimping equipment from European manufacturers.
• We make final testing.

The list of performed repair works will be constantly expanding.

What are the “symptoms” of a faulty shock absorber? It is impossible to visually determine the health of the shock absorber! Firstly, you will not see traces of oil, because the shock absorber rod is hermetically sealed with a pneumatic bellows, which does not even allow air to pass through. Secondly, the “manual pressure” method will not work in this case, because the shock absorbers are electronically adjustable for stiffness, which means they work under tension. The main symptom is a knock when crossing small irregularities (such as a speed bump). It indicates that there is an oil or gas leak in the shock absorber. If oil gets into the air spring, it will quickly destroy it.
Detailed troubleshooting of the shock absorber can only be carried out using special equipment. It will show problems in oil, gas, and hardness control valves.

How do we make repairs? The shock absorber is completely disassembled to identify defects. All parts and assemblies are rinsed. Replacement of: separator seals, bottom valve, shock absorber rod piston; Teflon rod guide; stem oil seal. The geometry of the shock absorber rod is checked. The operation of the ADS valves is checked. The shock absorber is being assembled. The oil is filled in, adapted to our climatic conditions. Gas is pumped in. The shock absorber undergoes a final check using special diagnostic equipment.

Here's what I found:
Air spring 370/260 (Trayal Serbia T-159) LiAZ, MARZ, Code: 5256-2934014, 762 rub.
Pneumatic balloon 370/260 (Poland AB 418) LiAZ, MARZ, Code: 5256-2934014, 980 rubles.
Air spring assembly with fittings, Code: 5256-2934014-01, 3160 rubles

The GAZ-elists club has been discussing this for a long time. As for me - it's worth it. The prices are real.

If you do it yourself - I think you can invest in $ 220 without a compressor. It's not 600 euros.

In Brest, there is a US-24022KPP available for 100 euros. Height 348mm, diameter 290mm, air spring travel about 140mm.

Air suspension makes driving easier and smoother when compared to shock absorbers. How does this element of the car work and does it have any drawbacks? DIY air suspension: how to do it, what is the difference between the installation of the front and rear suspension.

The pneumatic suspension allows you to adjust the ground clearance semi-automatically or completely without the use of physical effort. We are talking about replacing springs, springs and torsion bars with pneumatic bellows, in which the compressed air injected from the system acts as an elastic element. Despite all the advantages of this element, a do-it-yourself air suspension can be created only if you have basic car repair skills. The process is fraught with certain difficulties and a beginner clearly cannot cope with this.

The design of each air suspension is represented by a receiver, a control unit, an air distribution system and a compressor. To increase driver comfort, the suspensions can be automatic or manual.

1. Automatic air suspension assumes an independent selection of the height of the ground clearance by electronics, taking into account such factors as acceleration, speed, incline. The benchmark in this case is aimed at high aerodynamic performance. The center of gravity is lowered, therefore the machine's controllability is significantly increased.
2. Manual control requires the initiative of the driver when choosing the height of the ground clearance relative to the road. Manual adjustment is also possible in relation to the stiffness of the suspension, if its design assumes the presence of air shock absorber struts.

There are three modifications of pneumatic suspensions:

1. Single-circuit versions are designed to be installed on one axle and provide the same pressure in both cushions on it, since the compressor and cylinders are located on the same circuit.
2. Dual-circuit modifications are also installed on one axle, but in fact they are two single-circuit suspensions, thanks to which it is possible to adjust the height of the front and rear of the car relative to each other. The main disadvantage is the roll of the machine, since there is a pressure difference between the two wheels that run along the outer radius.
3. Four-circuit options are considered the best because four separate valves for each wheel, pressure sensors and a microcomputer are used for control. Therefore, the problem with the roll in this case is excluded, since the pillow stably holds the required pressure.