This article was written while working with a Skoda Octavia, front-wheel drive. There may be some differences on other models, but they do not affect the total volume or the method of repair.

The rear multi-link independent suspension is designed to provide comfort and steering precision at all speeds and on all surfaces. There are so many components in it that even schematically it is impossible to place in one drawing

And like any movable structure, it has its own resource.

Cars of this platform have been driving for a long time to collect statistics on the most frequently replaced components. These include the so-called thrusters and silent blocks in the rear lower wishbones. But in fact, in the rest of the levers, silent blocks of almost the same diameter. This means that they have approximately the same resource. But it is almost impossible to diagnose their condition visually. And it turns out that the hands reach them only when the camber / toe-in stand cannot touch the adjusting bolts. By the way, there are 4 of them.

And if the lower ones still have a chance to stir up or even cut off with a grinder, then the upper ones are very difficult to access

Therefore, in this article, we will consider the bulkhead of all elements of the rear suspension, with the removal of the beam.

While everything is firmly screwed to the body, it makes sense to "remove" all the nuts and bolts, which then need to be unscrewed

-disconnect the parking brake cable from the calipers. To do this, the "mustache" on the cable jacket must be squeezed

We take out the cable from the guides attached to the levers

Now you can unscrew the calipers themselves, and hang them on the locker using wire hooks, for example

In order not to depressurize the brake system, you need to disconnect the tubes from the beam. To do this, take out the clips.

Now you can bring both the tube and the hose to the side through the slot

We snap off the tube going to the right caliper along the beam from the clips

Unscrews the body position sensor from the lever (for those versions that have it)

We start dismantling. Place a stop under the rear arm and create a stop. Unscrew the bolt securing the lever to the steering knuckle

Lower the rack, lower the lever, remove the spring

Unscrew the lower shock absorber mounting bolt

On the left side, remove the muffler mounting rubber

Disconnect the connectors from the ABS sensors

We install the hydraulic rack under the beam

We unscrew the bolts securing the trailing arms

Unscrew the 4 bolts securing the beam to the body

The beam can be removed

Now let's start parsing.

We unscrew the outer bolts of the upper levers

Let's move on to the internal ones.

And if it is not very difficult to unscrew the nut, then the bolt itself most often turns out to be soured inside the bushing of the silent block. By the way: even in this position, it is almost impossible to determine the state of the silentblock itself

We take the "grinder" in our hands and cut off the bolt

We take out the lower bolts of the thrusters to the steering knuckle

Trying to unscrew the rear stabilizer post from the lever

Most likely it will not work.

Then we take the "grinder" in our hands again

We split the unscrewed parts so that they do not get confused during assembly

We unscrew the bolts attaching the trailing arms to the steering knuckles

We turn the beam over and unscrew the lower rear levers. And again, there is a possibility that the nuts will be unscrewed, but the bolts will not.

We pick up (in unison!) “Grinder ...

Unscrew the stabilizer mounting bolts

We unscrew the last levers, the very thrusters.

Suspension disassembled

And here is a set of new spare parts, awaiting installation

do not rush to rewrite the numbers from the boxes. This article does not discuss manufacturers and the method of repair (replacing silent blocks or the entire lever)

Install the thrusters first. Do not confuse left with right! (for some models, from a certain year, they may be symmetrical)

-Before pressing in new silent blocks, it is necessary to clean the seat

The silent block itself must be correctly oriented relative to the lever. It has two protruding stripes

They must be aligned with the protrusions of the lever.

To avoid displacement, you can apply a mark with a marker

And you also need to take into account that the silent block clip is narrower than the lever itself

And here the marker will help

Press in

However, a more accurate measuring instrument can also be used.

Install the levers into the beam, insert new bolts and new eccentric washers

We fasten the stabilizer in place, already with new struts

We turn the beam over, take the upper levers

Please note that the silent blocks are almost identical in appearance, differ only in their inner diameter.

We repress in the same way, only the head will need a different diameter

We fasten the levers to the beam, also using new bolts and washers

Now we take on the trailing arms. ELSA prescribes that certain dimensions must be adhered to during assembly and pressing,

I do this: before unscrewing the central bolt, I measure the distance between the lever and the body

Then you can already unscrew the central bolt

Before removing the old silentblock, it is convenient to make a mark on which to orient the new silentblock

By the way, it is possible to consider the separation of this silent block only after dismantling

The already familiar extraction procedure

we clamp the lever in a vice, install the body, bait the central bolt. We set the required distance, tighten it in advance, then clamp the body itself in a vice, and make the final tightening with a torque wrench.

The silent blocks remained in the steering knuckles themselves. To replace them with a press, you need to unscrew the caliper bracket, remove the brake disc, wheel bearing, and unscrew the boot. But with a small number of mandrels and a long screw, everything can be done on site.

I will share a little secret: the clip of these silent blocks is plastic, and to facilitate removal, you can use an industrial hair dryer or even a compact gas burner. Pop out "with a bang"

The reverse process is much easier.

All silent blocks have been replaced, you can proceed to reassembly. It makes no sense to describe the entire procedure, but it is worth paying attention to a few points:

- there are several washers in the bolt-nut bundle.

They are placed like this:

When screwing the trailing arm to the steering knuckle, do not tighten them immediately, as you must first insert the stabilizer bolt.

And in general, you cannot tighten any fasteners to a certain point, just make money and twist.

To make it more convenient to insert the beam into place, you can cut off the caps of a pair of old bolts, and use them as guides

This will make it easier to align the holes.

The springs must be installed in a strictly defined position. This can be helped by a protrusion on a rubber sole, which must be inserted into the mating hole of the lever.

A jack or hydraulic stand is placed under the lever.

Align the holes, insert the bolt, tighten the nut.

Jack up the lever until the weight rests on the spring

You can help determine this moment by the stop, a gap should appear between it and the body

And it is at this moment that all the bolts and nuts must be tightened.

Insert the brake pipe into the clips

Put the connectors on the ABS sensors

After that, you can screw on the wheels and go straight to the camber / toe stand.

For your own peace of mind, you can re-tighten all the bolts and nuts that secure the levers when the machine is on its wheels.

In general terms, the double wishbone suspension arrangement is quite simple. There are two levers, usually A-shaped, with the base of the triangle facing the wheel. The levers are fixed movably. The inner side of the lower arm is attached to the subframe or, if the body is not load-bearing, to the frame, the upper arm to the body. The outer side of the levers is movably connected to the rack carrying the wheel. In the case of the front suspension, the strut is swivel. Between the levers is a vibration-damping elastic element, which today usually consists of a spring and a telescopic shock absorber.

The greatest influence on the handling of a car equipped with such a suspension is exerted by the mutual arrangement of the levers and the ratio of their lengths. Short levers of the same length practically do not occur, since if they are available, when the car overcomes unevenness, the wheel will move not only in the vertical, but also in the horizontal direction. In other words, the track will change, which is an extremely undesirable effect from the point of view of handling. As a result, the upper arm is usually 1.5 to 1.8 times shorter than the lower one. This makes it possible to achieve such a change in the camber of the wheels so that the wheel external to the center of rotation (as the more loaded one) always remains perpendicular to the road surface, which in turn means the maximum ability to transfer the side load.

By the way, the MacPherson strut, which we talked about last time, can be considered an inverted "two-lever". The lack of lateral displacement of the upper end of the strut, characteristic of the MacPherson strut, is in fact equivalent to the very long upper arm in a double wishbone suspension. Now the nature of the kinematic flaws of the suspension on the guide strut becomes clear.

Other advantages of the double wishbone suspension are better sound insulation and transfer of less loads to the body, relative ease of repair.

There are also disadvantages. The cost of designing and maintaining such a suspension is higher than that of MacPherson, because the correct adjustment of the "two-lever" is a rather complex geometric task. In addition, the horizontal orientation of the suspension "eats up" space under the hood, as well as in the luggage compartment, when it comes to the rear suspension. As a result, a double wishbone suspension is now almost impossible to find on front-wheel drive compacts with a transverse motor. This type of suspension also complicates the design of body zones crumpled upon impact.

Additional complications arise with the use of double wishbones in the rear suspension. The fact is that the larger and more powerful the engine (that is, the higher the torque), the more the suspension arms bend during braking and acceleration. Most of the powerful cars are rear-wheel drive, and their natural instability is only exacerbated by this effect. Even with a simple release of the gas in a corner without pressing the brake pedal, negative toe-in of the wheels occurs ("socks apart"). The wheel external in relation to the bend as more loaded determines the behavior of the car, and the car shows a pronounced oversteer until it loses control.

It is for this reason that the continuous rear axle did not give up its positions for a long time. But technological progress will sooner or later solve any problem. First, the Porsche engineers, faced with the difficulties described in the 928 with an 8-cylinder engine in the front, decided to turn the elasticity of the levers to the advantage of the case. They attached longitudinal "breaking" links to the lower arms of the rear suspension. When the wishbones are bent back during braking, the rods turn the wheels "toes inward".

The Porsche 928 was truly renowned for its handling, and the solution was named the Weissach Bridge, after the town of Weissach in Baden-Württemberg, where the Porsche test site is located. It was a piecemeal solution that paved the way for a more replicable solution.

In 1982, the designers of Daimler-Benz on the 190 (W201) used the world's first multi-link rear suspension. Despite the fact that there were five levers on each side, it was still the same "two-lever", only all its "twists" were now suppressed by additional levers. The upper and lower arms in the suspension are double (which already gives four in total), and in plan they form a trapezoid. When the ends of the levers are moved back during braking, the sides of the trapeziums work in much the same way as the rods of the Weissach bridge, giving the wheels a reverse motion, and so eliminate instability. The fifth lever is oriented obliquely forward and, when the machine rolls sideways, steers in favor of light understeer, regardless of the amount of braking.

Since the distant 80s, most high-speed cars have a multi-link rear suspension, made according to a similar principle. Of course, the task of positioning the levers in this case is much more complicated and requires careful three-dimensional computer modeling, which greatly limits the use of "multi-link". For example, at the “golf-class” level, this decision can serve as a criterion for the model to belong to the premium segment of this market sector. The presence of a multi-link suspension on the rear wheels reduces the requirements for the front suspension, so it is not uncommon to combine an inexpensive MacPherson strut on the front wheels with an advanced “multi-link” rear.

The shock absorber is a hydraulic unit consisting of a body in the form of a cylindrical tube with smooth inner walls, filled with a working fluid (in the automotive industry - oil). Inside the body there is a piston connected to a rod. When the rod is compressed, the piston, as if in a syringe, presses the working fluid. Which is forced to flow from one cavity (under the piston) to another (above the piston in a single-tube shock absorber or into the cavity between the bodies - in a two-tube shock absorber). For this, special calibrated valves are provided. Depending on the design, the upper end of the rod and / or the lower eye of the shock absorber have holes with a pressed-in rubber bushing - for attaching the unit to the body and suspension arms.

By selecting the capacity of the valves, you can adjust the required compression and rebound damping characteristics of the shock absorber. The difference between these values ​​determines the ability of shock absorbers to effectively damp vibrations in the suspension (quickly, progressively compress, "taking a hit", and slowly unfold - so as not to provoke multiple body vibrations).

Other names

"One-pipe" (slang name for a one-pipe shock absorber), "two-pipe" (respectively, the name of a two-pipe shock absorber). For McPherson type suspensions, the shock absorber is sometimes referred to as a "strut", although this term is more correct to refer to the entire assembly, and not just to the shock absorber.

Appointment

A shock absorber is a mandatory attribute of the suspension of any car, designed to damp / prevent repeated vibrations and / or swaying of the body when the car is moving on bumps.

Without shock absorbers, the suspension springs will compress and expand - under the action of external forces when driving through road irregularities - in self-oscillation mode (possibly with a growing amplitude). Shock absorbers are designed to dampen these vibrations. In general, ride comfort, as well as handling characteristics, very much depend on the type of shock absorbers, their serviceability and even operating temperature (it is not uncommon for shock absorbers to "boil" during intensive work - for example, on a bumpy road or heavy off-road terrain).

Malfunction symptoms

A defective shock absorber can be identified by a characteristic knock from under the bottom of the car - the cause, as a rule, is a worn mount. Upon visual inspection, black oil drips on the shock absorber housing eloquently indicate its failure.

In motion, faulty shock absorbers lead to a lack of effective damping of vibrations - the car body sways, "dances" on irregularities.

The most reliable data on the condition of shock absorbers (their serviceability and residual life) can be obtained when testing a car on a vibration stand. A modern computerized stand takes into account the design of the suspension (the brand of the car is entered into memory before testing) and checks the shock absorbers and other suspension parts, simulating real road loads. Thus, the test data indicates the operating condition or the need to replace the shock absorbers. At the same time, the price of the service will be determined by both the cost of new shock absorbers and the amount of work on dismantling / installing struts (which does not differ much for cars of different brands).

Replacing shock absorbers

The cost of replacing shock absorbers is largely determined by the type of suspension. In principle, a distinction should be made between the double wishbone suspension and the McPherson strut design. In the second case, the repair of shock absorbers will be assessed based on the total cost of removing the front struts, disassembling them, replacing the front shock absorber, reassembling the rack and installing it.

Multi-link rear suspension may also require replacement of the rear suspension struts. For a dependent suspension arrangement, replacing the rear shock absorbers is generally easier. Below are typical cases of suspension repair by replacing shock absorbers.

Replacing the front shock absorbers (with a double wishbone):

• the operation is performed on a "pit" or on a lift (you do not need to raise the car high - for the convenience of replacing the suspension should be slightly compressed!);
• open the hood, through the hole in the engine compartment, unscrew the upper rod fastener (to fix it from turning, you must hold the rod with a special key or thin pliers);
• completely remove the rod fasteners, engraving and support washer of the cushion - then you can remove the upper support cushion of the shock absorber itself;
• under the lower suspension arm, unscrew the two nuts securing the shock absorber support (carefully so as not to lose the self-tightening washers!);
• the old shock absorber is removed downwards - through the window of the lower suspension arm;
• on the removed shock absorber, the rubber support cushion is removed from the rod;
• using two keys, the bracket fastening nut is unscrewed (the bolt head is held with the second key) - and the entire bracket is removed;
• The removed bracket can be moved to another shock absorber - if the new unit is supplied without it!
• the new shock absorber is installed in the reverse order (before installation, it is recommended to extend its stem as much as possible! And in advance put a washer, a pillow on the upper end, and also attach a nut);
• the second shock absorber of the front suspension changes in the same way.

Replacing the front struts like McPherson:
Since the McPherson strut includes both a shock absorber and a front suspension spring (with two support cups) and a telescopic rod, as well as a number of other parts, replacing the shock absorber will involve completely removing the strut and disassembling it. Very often this operation is also called: "replacing the shock absorber strut", or simply "replacing the strut" - although it still means replacing the shock absorber. The work algorithm is as follows:

• the car is installed on a flat area or hung out on a lift;
• the hood opens, the nut securing the support to the rack is slightly loosened (while the shock absorber rod should be held with the second key);
• the handbrake is tightened, the wheel bolts are loosened;
• the right side of the car is lifted by a jack (if the operation is not carried out on a lift);
• the wheel is removed, the front brake hose is carefully laid aside (first, remove it from the holder on the rack);
• to facilitate the replacement of the shock absorber strut, it is recommended to thoroughly clean all bolts and nuts from dirt (especially the strut mount to the steering knuckle) and lubricate with WD-40 grease;
• the fastening of the steering tip to the rack arm is unscrewed, using a hammer (or better, a special puller!) the tip is knocked out of the rack;
• the nuts connecting the rack and the steering knuckle are unscrewed from below (it is better to use union heads with a crank);
• certain difficulties may arise with removing the bolts from the mounting sockets - they should be carefully knocked out with a thin metal rod, periodically unscrewing the bolt from the back side;
• finally, under the hood, the three nuts securing the strut to the support cup of the body are unscrewed (do not completely unscrew the last nut so that the strut does not fall down!)
• when the fasteners of the strut to the knuckle are removed, you can finally unscrew the upper nut fastening to the body cup and remove the strut.

To replace the shock absorber, the rack should be disassembled:

• using a tie, it is necessary to compress the spring of the rack (while placing the legs of the ties evenly so that the spring does not warp);
• as soon as the spring moves away from the support plate, you can unscrew the upper nut;
• the strut support is removed (together with the bearing and rubber cushions - so as not to assemble this unit in detail when installing a new shock absorber);
• the compressed spring is removed (if necessary, it can be replaced with a new one - simultaneously with replacing the shock absorbers of the strut);
• the boot and bump stop are removed from the rack stem (they are fitted with an interference fit - you need to apply a little effort!);
• a bump stop and a boot (previously removed or also new) are put on the new stands;
• a new spring is installed (before installation, it is also pulled together to fit under the support cups of the rack);
• the spring is put on the rack - you need to make sure that the lower coil exactly sits on the support belt!
• the upper support cup is turned over - a bearing is placed on it (there is always a “top” mark on the outer bearing ring);
• the bearing is covered with a cup, an elastic band is installed on top - the resulting "pact" is put on the strut rod with a new spring and tightened with a nut (while the strut rod must be kept from turning);
• when tightening the nut, make sure that the upper coil of the spring lies exactly along the perimeter of the support cup!
• the assembled module of the new rack is installed on the vehicle in the reverse order of removal of the rack (see above).

As you can see, the cost of replacing the struts (as well as the list of necessary work) can be higher than the cost of replacing shock absorbers on a double wishbone suspension.

It should be noted that the rear multi-link suspension also contains struts. Accordingly, the work on their replacement will be somewhat complicated (compared to replacing the rear shock absorbers of the dependent suspension, this is usually much easier).

What needs to be done by car:

For a double wishbone suspension, replacing the shock absorbers does not affect the wheel alignment angles. But the replacement of the front shock absorbers and / or McPherson struts in the assembly should always be accompanied by the subsequent adjustment of the wheel alignment and camber!

Such additional work as replacing the support bearing, replacing the strut support, etc., require disassembling the entire unit. This means that it is logical to perform them simultaneously with the replacement of the front pillars.

When carrying out work, it is recommended to check the rest of the suspension units (in particular, the condition of the silent blocks, steering rod ends, ball bearings, stabilizers and suspension arms, as well as the integrity of the brake hoses, wheel bearing oil seals, etc.).

By the way, in order to prevent damage / contamination of the CV joint boot, it is recommended to close the CV joint grenade with polyethylene when replacing shock absorbers or replacing shock absorber struts.

Shock Absorber Life

The resource of the suspension elements largely depends on the condition of the roads, driving style, and the typical load of the car. And also on the climate, car brand and a number of other important factors. Therefore, the service life of individual elements can vary significantly and any figures should be taken as indicative only. For shock absorbers, the resource is about 30 thousand km of run, but in fact it can be either less or much more than this value.

What threatens an untimely replacement

Operating a car with faulty shock absorbers leads to a sharp deterioration in comfort when driving (increased swing, "roll", the car responds poorly to the steering wheel). In addition, like any suspension element, the shock absorber affects the stability and handling of the car, that is, its active safety.
And since we are talking about safety, the cost of replacing shock absorber struts turns out to be incomparably less than the possible consequences of ignoring the malfunction!

The characteristics of the suspension elements have a decisive influence on the handling and ride quality of the vehicle. And if it is almost impossible to change levers, springs, ball joints and silent blocks in search of the best "habits" of a car on the road, then it is quite possible to "play" with the characteristics of shock absorbers (even by their multiple selection and replacement)!
In addition to the special struts, which the manufacturer positions as sports shock absorbers (and which really improve the responsiveness and make the car "sharper"), there are customizable shock absorbers. When installed, it becomes possible to easily change the response to compression and rebound (separately), adapting the car to one or another track conditions. At the same time, the installation and replacement of shock absorber struts is no different from that for the original equipment!

Do not confuse "gas" shock absorbers and gas stops. The latter are used, for example, to hold the bonnet or trunk lid. These stops consist of a cylindrical tubular body and a movable rod - in this they really look like shock absorbers. But inside the body, the stops contain gas under pressure, which prevents the rod from sharply compressing - this provides the holding property of the stop. Although with a little more force, it can be easily "defeated" and squeezed, folded until the stem is completely inside the body.

In a "gas" shock absorber, the working fluid is oil - normally it is not under pressure. But if external forces (tensile or compressive) are applied to the rod, the shock absorber "rests" because the viscous oil dissipates the energy of the external influence through its throttling through the working valves. To improve the characteristics of the shock absorber, inside its body, closer to the lower end, there is a small volume filled with gas (most often nitrogen) and covered with a solid piston. This kinematic piston is not associated with a rod piston. But when the oil pressure rises, this additional piston compresses the gas volume. At the same time, the gas “does not go anywhere” and does not mix with the main working oil. But the presence of such a sealed "spring-loaded cavity" inside the body has a beneficial effect on the operation of the shock absorber - due to the difference in the viscosity of the compressed oil and gas.

Thus, the "gas" shock absorber still remains liquid. But with improved damping performance.

Double wishbones are a common type of independent suspension. The design of the double wishbone suspension is based on the use of two levers, an upper and a lower one, attached at one end to the body, and the other to the wheel hub. At the dawn of the automotive era, cars differed from horse-drawn carriages only by the presence of an engine. Accordingly, the suspension in the form of a beam on elliptical springs migrated to them practically unchanged. However, as the speed of cars increased, its imperfection made itself felt more and more, and as a result of the efforts of engineers and inventors, it had a double wishbone. Cars of the early twentieth century, so unlike modern ones, were far from the concepts of "comfort" and "handling". And this is exactly what the buyers of not cheap cars lacked. Acceptable driving performance was achieved with the beginning of the use of independent suspensions. They, like most automotive developments, migrated to civilian cars from motorsport. High speeds and dependent suspensions turned out to be incompatible things. Handling on bends remained at the level of the same horse-drawn carriages. In addition, the car body was located above the bridge girders, so the center of gravity was high. And if when driving in a straight line there were no problems, then fast turns had to be overcome almost at the speed of pedestrians. Despite the fact that the double wishbone suspension appeared on cars even before World War II, it is still considered the most balanced and optimal for a passenger car. In addition, on the cars of the most famous Formula 1 racing series, a "two-lever" is used. Russian motorists are not by hearsay familiar with this design - on, from "Kopeyka" to "Seven", the front suspension was independent, double wishbone.

Double wishbone design

Also, like almost a hundred years ago, it consists of two levers located transversely, one above the other. The lower one, through the silent blocks, rests on a beam or subframe, and the upper one - on the body. Other ends of the arms. Different arm lengths are used to save space and achieve optimal suspension kinematics. The upper, short, is made in the form of the letter "A", and the lower, in the form of the letter "L". A spring, torsion bar, pneumatic spring or semi-elliptical spring can be used as an elastic element in a double-wishbone suspension. True, the latter is practically not found on passenger cars and is used only on light trucks. Together with a shock absorber, an elastic element is attached at one end to the lower arm, and the other to the car body.

Pros and cons of double wishbone suspension

As mentioned above, the independent double wishbone suspension gives the car good handling. But this is not its only advantage. When driving over irregularities, shocks during operation of the suspension are damped more efficiently, which for the better affects the level of ride comfort. And most importantly, this type of independent suspension is by far the most reliable. If it is so good, then why is it not installed on all cars? The problem is that the double wishbone suspension has a significant drawback. The fact is that the upper lever “eats up” the engine compartment quite noticeably. And if we consider that the overwhelming majority of modern cars are front-wheel drive, with a transverse engine arrangement, then the "two-lever" simply does not have room in the body. Therefore, almost all A-, B- and C-class cars are content with a compact and cheaper to manufacture. For the same reason, the double wishbone suspension is practically not used on the rear axle of cars, because it reduces the useful volume of the trunk. Sooner or later, any, even the most reliable, suspension wears out. Here one more minus of the "two-levers" pops up. The fact is that now the levers are made non-separable. That is, both the ball joint and the silent blocks are made in one piece. And the levers themselves, to reduce unsprung masses, are mainly made of aluminum. Therefore, when, say, "penny" silent blocks or a ball joint are worn out, you have to buy an expensive lever entirely. The state of the suspension elements can be diagnosed on your own. To do this, it is enough to jack up the desired wheel, and then, using the assembly, check the condition of the ball bearings and silent blocks. The latter are most often calculated for the entire service life of the vehicle and do not require attention. But the most vulnerable places in the double wishbone suspension are the ball joint and the shock absorber. Despite the simplicity of the design, it is better to entrust repairs to professional car mechanics, but, with the appropriate skills, devices and desire, you can do it yourself.

Because for any vehicle, one of the most important systems affecting comfort and safety while driving is the suspension. Designing a multi-link suspension as the best choice is an important consideration for the automaker. For the first time they started talking about it back in the middle of the last century, and today it has received well-deserved recognition and demand for most passenger cars, rear- and all-wheel drive, where it is most often installed on the rear axle.

The device and principle of operation of the multi-link suspension

Almost any multi-link suspension includes a number of essential elements:

• levers - longitudinal and transverse;
• hub support;
• stretcher;
• shock absorbers and springs.

Instead of the last two elements, a pneumatic strut can be used. The main role in the multi-link rear suspension is played by a subframe, to which transverse levers are attached, which, in turn, are connected to the hub support. This version of the suspension can consist of three or five levers.

The process of designing a multi-link suspension is very complex, and is carried out only with the help of computer modeling. Each lever in this system is responsible for a certain moment in the behavior of the wheel - a change in lateral movement or camber. As a rule, designers provide for the independent work of each link in such a mechanism, and often the levers are given a strictly defined shape, which is necessary for engineers to create a body of the intended shape. You can learn about the evolution of the suspension and its main features by watching the video:

The benefits of a multi-leverage system

In many cars, especially those not in the premium segment, concepts such as comfort and good handling are often mutually exclusive. The creation of a multi-link independent suspension allowed the designers to make almost any car comfortable for passengers, and at the same time easy to operate. Among the main advantages of the course multi-link suspension are the following:

• all wheels of one axle are completely independent of each other;
• the possibility of using aluminum parts in the structure allows to reduce the weight of the suspension itself;
• excellent adhesion of each wheel to the road surface, which is especially important when driving on a wet track or on ice;
• maintaining optimal control of the car even at high speed, sharp maneuvering and high-speed passage of sharp turns;
• thanks to powerful silent blocks, with the help of which the elements of the multi-link suspension are attached to the subframe, it was possible to achieve good insulation of the cabin from noise;
• the ability to use in vehicles equipped with front, rear or all-wheel drive.

It has a multi-link suspension not only pluses, but also minuses. The main one should be noted the complexity of the design. In addition, most car manufacturers see the need to install non-separable levers, the cost of which is very impressive. For a multi-link suspension, roads with high-quality surfaces are highly desirable, which in our country is the exception rather than the rule. hence - the frequent need for repairs, which are difficult to carry out on their own, and contacting specialists is not cheap.

Is it possible to keep the multi-link suspension on bad roads

Despite the rather expensive operation, car owners almost never have doubts about which is better - a beam or multi-link suspension. In terms of comfort and safety, these systems are simply incomparable. Keeping this type of suspension in optimum condition requires constant monitoring and maintenance. Despite the complexity of the entire structure, many care manipulations can be performed independently. Especially in the presence of a viewing hole or lift.

When servicing a multi-link suspension, you must first of all be guided by the manufacturer's recommendations set out in the manual. First of all, the shock absorbers are checked - the presence of cracks, dents or smudges indicates the need for replacement. After that, rods, ball, silent blocks are subject to inspection. Attention is paid to the fasteners, which are tightened if necessary, as well as to all rubber seals. The multi-link rear axle suspension may be suspicious to inexperienced drivers if there is an abnormal noise when driving from behind.

It is named after the American Ford engineer Earle Steele MacPherson, who first used it on a 1948 Ford Vedette production car. It was later used on Ford Zephyr (1950) and Ford Consul (1951) vehicles. It is the most common type of independent suspension that is used on the front axle of a car.

By design, the MacPherson strut is a development of the double wishbone x, in which the upper wishbone is replaced by a shock strut. Due to its compact design, the McPherson suspension is widely used in front-wheel drive cars, since it allows the engine, gearbox and other attachments to be placed laterally in the engine compartment. The main advantage of this type of suspension is its simplicity of design, as well as a long suspension travel, which prevents breakdowns. At the same time, the design features of the suspension (pivot mount of the shock absorber strut, long travel) lead to a significant change in the camber (the angle of inclination of the wheel to the vertical plane). When cornering, camber goes into a plus, the wheel turns under the car, as it were, and therefore the car's ability to turn at high speed sharply deteriorates. This is the main disadvantage of the MacPherson strut, which is why this type of suspension is not used on sports cars and premium cars.

The MacPherson suspension has the following device:

1.spring

2.strut of shock absorber

3.Rod of anti-roll bar

4.Circle wishbone with ball joint

5.subframe

6.steering knuckle

The suspension is attached to the body via a subframe, which is the supporting structure. It is rigidly attached to the body or through bushings to reduce vibrations transmitted to the body. On the side of the subframe, two triangular wishbones are attached, which are connected to the steering knuckle through a ball joint. The steering knuckle rotates the wheel due to the steering rod, which is attached to it from the side. Shock absorbers with springs installed on them are attached directly to the steering knuckle. Two rods from the lateral shock absorber are connected to the shock absorbers through ball joints, which are responsible for lateral stability. As you can see, the suspension device is simple enough to describe it in 3 lines.

Advantages and disadvantages

pros

+ low cost

+ easy to maintain

+ compactness

- Poor cornering control

- Transmission of road surface noise to the body

MacPherson suspension video:

2. Double wishbone suspension ( Double wishbone suspension)

Unfortunately, it is still not known for certain who first invented the double wishbone suspension; it first appeared in the early 30s on Packard cars. This company was based in the heart of the American automotive industry, Detroit. The first Packard car rolled off the assembly line in 1899, the last was built in 1958. After the 1930s, many American cars began to be equipped with double wishbones, which cannot be said about Europe, because due to the size of the car, there was not enough space to accommodate such a suspension. Much time has passed since then and now double wishbone suspension is considered the ideal type of independent suspension. Due to its design features, it provides better control over the position of the wheel relative to the road, because the double levers always keep the wheel perpendicular to the road, for this reason, the handling of such cars is much better.

The double wishbone suspension can be applied to the front and rear axles of the vehicle. The suspension is used as the front suspension on many sports cars, executive and business sedans, and Formula One cars.

Double wishbone suspension device:

1.upper wishbone
2.shock absorber
3.spring
4.drive shaft
5.Steering rod
6.lower wishbone

The double wishbone suspension design includes two wishbones, a spring and a shock absorber.

Lever arm can be Y-shaped or U-shaped. Unlike MacPherson, there are two levers, each of the levers is attached to the body through silent blocks and to the steering knuckle through a ball joint. The upper lever, as a rule, has a shorter length, which gives a negative camber angle during compression and positive - when stretched (rebound ). This property gives additional stability to the car when cornering, leaving the wheel perpendicular to the road regardless of the position of the body.

Advantages and disadvantages

pros

+ perpendicular position of the wheel relative to the road in bends

+ resistance to pecks

+ improved handling

Minuses

- big size

- price

- labor intensive maintenance

Video of the double wishbone suspension

3. Multi-link suspension (Multilink).

Further development of the double wishbone suspension. This is the most common rear axle suspension available today. This is due to the fact that when using a double wishbone suspension when braking or dumping gas (on rear-wheel drive vehicles), the convergence angle of the rear wheels changes. Because the suspension is attached to the subframe through silent blocks, which deform during braking and the rear wheels begin to look outward. It would seem that there is nothing wrong with this phenomenon, but imagine that you went too far with the speed in a turn and decided to resort to braking, braking in a turn is not a good idea in itself. And then the external loaded wheel begins to look outward of the turn, the car very quickly becomes oversteer and the consequences can be the most sad. It is possible to prevent this phenomenon by replacing the silent blocks with articulated joints, but then comfort will suffer greatly, because no one wants to chatter their teeth on the bumps. Therefore, the engineers took a different path.

The car suspension is a set of elements that provide an elastic connection between the body (frame) and the wheels (axles) of the car. Mainly, the suspension is designed to reduce the intensity of vibration and dynamic loads (shocks, shocks) acting on a person, the transported cargo or structural elements of the vehicle when driving on an uneven road. At the same time, it must ensure constant contact of the wheel with the road surface and effectively transmit the driving force and braking force without deviating the wheels from the corresponding position. Correct suspension function makes driving comfortable and safe. Despite the apparent simplicity, the suspension is one of the most important systems of a modern car and has undergone significant changes and improvements over the history of its existence.

History of appearance

Attempts to make the movement of a vehicle softer and more comfortable were made even in carriages. Initially, the axles of the wheels were rigidly attached to the body, and every unevenness in the road was transmitted to the passengers sitting inside. Only soft seat cushions could improve the level of comfort.

Dependent suspension with transverse leaf springs

The first way to create an elastic "layer" between the wheels and the carriage body was the use of elliptical springs. Later, this solution was borrowed for the car. However, the spring had already become semi-elliptical and could be installed transversely. A car with such a suspension handled poorly even at low speeds. Therefore, soon the springs began to be installed longitudinally on each wheel.

The development of the automotive industry has led to the evolution of the suspension. Currently, there are dozens of their varieties.

The main functions and characteristics of the car suspension

Each suspension has its own characteristics and working qualities that directly affect the handling, comfort and safety of passengers. However, any suspension, regardless of its type, must perform the following functions:

1. Absorbing shocks and shocks from the road to reduce stress on the body and increase driving comfort.
2. Vehicle stabilization while driving by ensuring constant contact of the tire with the road surface and limiting excessive body roll.
3. Preservation of the specified travel geometry and position of the wheels to maintain precise steering while driving and braking.

Rigid Suspension Drift Car

The vehicle's rigid suspension is suitable for dynamic driving, which requires an instant and precise response to the driver's actions. It provides low ground clearance, maximum stability, roll and body roll resistance. It is mainly used in sports cars.

Luxury car with energy-intensive suspension

Most passenger cars use a soft suspension. It smoothes out irregularities as much as possible, but makes the car a little rolly and worse controllable. If an adjustable stiffness is required, a helical suspension is mounted on the vehicle. It is a shock absorber rack with variable spring tension.

Long-stroke suspension SUV

Suspension travel - the distance from the uppermost position of the wheel when compressed to the lowest when hanging the wheels. Suspension travel largely determines the off-road capabilities of the vehicle. The larger its value, the larger the obstacle can be overcome without hitting the limiter or without sagging the driving wheels.

Suspension device

Any car suspension consists of the following basic elements:

1. Elastic device- perceives loads from unevenness of the road surface. Types: springs, springs, pneumatic elements, etc.
2. Damping device- dampens body vibrations when driving through bumps. Types: all types.
3. Guiding device—provides a predetermined movement of the wheel relative to the body. Views: levers, transverse and jet rods, springs. Pull-rod and push-rod sport suspensions use rockers to change the direction of action on the damping element.
4. Anti-roll bar- reduces lateral body roll.
5. Rubber-metal hinges- provide an elastic connection of the suspension elements to the body. Partially absorb, cushion shocks and vibrations. Types: silent blocks and bushings.
6. Suspension travel stops- limit the travel of the suspension in extreme positions.

Suspension classification

Basically, suspensions are divided into two large types: and independent. This classification is determined by the kinematic diagram of the suspension guide.

Dependent suspension

The wheels are rigidly connected by means of a beam or continuous bridge. The vertical position of a pair of wheels relative to the common axis does not change, the front wheels are swivel. The rear suspension device is similar. There is a spring, spring or pneumatic. In the case of installing springs or pneumatic bellows, it is necessary to use special rods to fix the bridges from moving.

Differences between dependent and independent suspension

• simple and reliable in operation;
• high carrying capacity.

• poor handling;
• poor stability at high speeds;
• less comfort.

Independent suspension

The wheels can change their vertical position relative to each other, while remaining in the same plane.

• good handling;
• good vehicle stability;
• great comfort.

• more expensive and complex construction;
• less reliability during operation.

Semi-independent suspension

Semi-independent suspension or torsion beam Is an intermediate solution between dependent and independent suspension. The wheels are still connected, but there is a possibility of them moving slightly relative to each other. This property is provided due to the elastic properties of the U-shaped beam connecting the wheels. This suspension is mainly used as the rear suspension for budget cars.

Types of independent suspensions

McPherson

- the most common front axle suspension in modern cars. The lower arm is connected to the hub by means of a ball joint. Depending on its configuration, longitudinal jet thrust can be used. An amortization strut with a spring is attached to the hub unit, its upper support is fixed to the body.

The transverse link, fixed to the body and connecting both levers, is a stabilizer that counteracts the roll of the car. The lower ball joint and shock absorber cup bearing allow for wheel rotation.

The rear suspension parts are made according to the same principle, the only difference is that there is no possibility of turning the wheels. The lower arm is replaced with longitudinal and transverse rods that fix the hub.

• simplicity of design;
• compactness;
• reliability;
• inexpensive to manufacture and repair.

• average handling.

Double wishbone front suspension

More efficient and sophisticated design. The upper attachment point for the hub is the second wishbone. A spring or torsion bar can be used as an elastic element. The rear suspension has a similar structure. This suspension arrangement provides better vehicle handling.

Air suspension

Air suspension

The role of springs in this suspension is performed by compressed air bellows. With there is the possibility of adjusting the height of the body. It also improves ride quality. Used on luxury cars.

Hydraulic suspension

Adjusting the height and rigidity of the Lexus hydraulic suspension

The shock absorbers are connected to a single closed circuit with hydraulic fluid. makes it possible to adjust the rigidity and ride height. If the vehicle has control electronics and functions, it automatically adjusts to the road and driving conditions.

Sports independent suspension

Helical suspension (coilovers)

Helical suspension, or coilovers - shock absorbers with the ability to adjust the stiffness directly on the car. Thanks to the threaded connection of the lower spring stop, its height can be adjusted, as well as the amount of ground clearance.

Because for any vehicle, one of the most important systems affecting comfort and safety while driving is the suspension. Designing a multi-link suspension as the best choice is an important consideration for the automaker. For the first time they started talking about it back in the middle of the last century, and today it has received well-deserved recognition and demand for most passenger cars, rear- and all-wheel drive, where it is most often installed on the rear axle.

The device and principle of operation of the multi-link suspension

Almost any multi-link suspension includes a number of essential elements:

• levers - longitudinal and transverse;
• hub support;
• stretcher;
• shock absorbers and springs.

Instead of the last two elements, a pneumatic strut can be used. The main role in the multi-link rear suspension is played by a subframe, to which transverse levers are attached, which, in turn, are connected to the hub support. This version of the suspension can consist of three or five levers.

The process of designing a multi-link suspension is very complex, and is carried out only with the help of computer modeling. Each lever in this system is responsible for a certain moment in the behavior of the wheel - a change in lateral movement or camber. As a rule, designers provide for the independent work of each link in such a mechanism, and often the levers are given a strictly defined shape, which is necessary for engineers to create a body of the intended shape. You can learn about the evolution of the suspension and its main features by watching the video:

The benefits of a multi-leverage system

In many cars, especially those not in the premium segment, concepts such as comfort and good handling are often mutually exclusive. The creation of a multi-link independent suspension allowed the designers to make almost any car comfortable for passengers, and at the same time easy to operate. Among the main advantages of the course multi-link suspension are the following:

• all wheels of one axle are completely independent of each other;
• the possibility of using aluminum parts in the structure allows to reduce the weight of the suspension itself;
• excellent adhesion of each wheel to the road surface, which is especially important when driving on a wet track or on ice;
• maintaining optimal control of the car even at high speed, sharp maneuvering and high-speed passage of sharp turns;
• thanks to powerful silent blocks, with the help of which the elements of the multi-link suspension are attached to the subframe, it was possible to achieve good insulation of the cabin from noise;
• the ability to use in vehicles equipped with front, rear or all-wheel drive.

It has a multi-link suspension not only pluses, but also minuses. The main one should be noted the complexity of the design. In addition, most car manufacturers see the need to install non-separable levers, the cost of which is very impressive. For a multi-link suspension, roads with high-quality surfaces are highly desirable, which in our country is the exception rather than the rule. hence - the frequent need for repairs, which are difficult to carry out on their own, and contacting specialists is not cheap.

Is it possible to keep the multi-link suspension on bad roads

Despite the rather expensive operation, car owners almost never have doubts about which is better - a beam or multi-link suspension. In terms of comfort and safety, these systems are simply incomparable. Keeping this type of suspension in optimum condition requires constant monitoring and maintenance. Despite the complexity of the entire structure, many care manipulations can be performed independently. Especially in the presence of a viewing hole or lift.

When servicing a multi-link suspension, you must first of all be guided by the manufacturer's recommendations set out in the manual. First of all, the shock absorbers are checked - the presence of cracks, dents or smudges indicates the need for replacement. After that, rods, ball, silent blocks are subject to inspection. Attention is paid to the fasteners, which are tightened if necessary, as well as to all rubber seals. The multi-link rear axle suspension may be suspicious to inexperienced drivers if there is an abnormal noise when driving from behind.

The exhaust pipe is a common cause of this. When checking it yourself, you should pay attention to it first of all - its fastening must be reliable, and if it is loose, it is enough to tighten it so that the extraneous sound disappears. It is quite dangerous to ride a car in the multi-link suspension of which damaged elements were found. So, a slightly bent lever causes the angle of the wheel, which leads not only to rapid wear of the rubber, but also noticeably changes the behavior of the car on the road for the worse.

Nowadays, different types of suspensions are installed on cars. There are dependent and independent. Recently, a semi-independent rear beam and a MacPherson strut have been installed on budget class cars. On business and premium cars, an independent multi-link suspension has always been used. What are the pros and cons of it? How does it work? About all this and not only - further in our today's article.

Characteristic

The multi-link suspension is installed on vehicles with rear- and front-wheel drive configurations. It has a more complex device, therefore it is used on expensive cars. For the first time, a multi-link suspension was installed on the Jaguar E-Tour in the early 60s. Over time, it has been modernized and is now actively used on Mercedes, BMW, Audi and many others.

Device

What are the features of this design? Multi-link suspension assumes the following elements:

• Stretcher.
• Transverse and trailing arms.
• Hub supports.
• Shock absorbers and springs.

How is it all fixed?

The hub is attached to the wheel by means of four levers. This allows the vehicle wheel to move freely in the lateral and longitudinal plane. The supporting element in the structure of this suspension is a subframe.

The wishbone is attached to it through special bushings with a metal base. They use rubber to reduce vibrations. The wishbones are connected to the hub support. This ensures the correct position of the wheels in the transverse plane. Often, a multi-link independent rear suspension includes three wishbones:

• Lower back.
• Front.
• Upper.

The latter carries out the transfer of forces and connects the subframe to the wheel support housing. The lower one is responsible for convergence. The rear element absorbs the forces that are transmitted from the body when the vehicle is moving. The wheel is guided in the longitudinal position by means of a trailing arm. It is attached to the car body with a support. On the other hand, the element is connected to the hub.

A passenger car has four trailing arms, one for each wheel. The hub bearing itself is the base for the wheel and bearing. The latter is fastened with a bolt. By the way, if you do not observe its tightening torque, you can damage the bearing. When making repairs, you should leave a slight backlash in the hub. Otherwise, your bearing will crumble. Also, the multi-link front suspension has a coil spring in its design. It rests on the lower rear wishbone and absorbs forces from it. A shock absorber is located separately from the spring. It usually connects to the hub support.

Stabilizer

A multi-link, in contrast to a semi-independent beam, has an anti-roll bar in its design. The name itself speaks for the purpose of the element. This part reduces roll when cornering at speed. Also, this parameter is influenced by the stiffness of the shock absorbers and springs. The presence of a stabilizer significantly reduces the risk of skidding when cornering, as it ensures uninterrupted contact of the wheels with the road surface. The element is a kind of metal bar. It looks like the photo below.

Mounted on a multi-link subframe and secured with rubber mounts. Thanks to the rods, the rod is connected to the hub support. What are the pros and cons of a multi-link suspension? Let's take a look at them below.

Advantages

Cars using this suspension are much more comfortable. The design uses several levers. All of them are mounted on stretchers through silent blocks. Thanks to this, when passing through a hole, the suspension perfectly swallows all irregularities.

By the way, the lever works only for the wheel that fell into the pit. If it is a beam, all efforts will be transferred to the adjacent hub. In a car where a multi-link suspension is used, unnecessary noise and vibrations are not felt when passing through uneven roads. Also, this car is safer. This is explained by the use of a stabilizer bar. In terms of their weight, the levers are much lighter than the beam. This reduces the vehicle's unladen sprung weight.

Thus, a multi-link suspension is:

• Comfort.
• Lack of strong impacts on the body.
• Increased traction.
• Possibility of lateral and longitudinal adjustment.

disadvantages

If the question is raised which is better - a beam or a multi-link suspension - it is worth considering the cons of the latter. The biggest drawback is the complexity of the design. Hence the high cost of maintenance and the expensive price of the car itself.

The cost of a multi-link suspension is 2-3 times higher than that of a conventional semi-dependent beam. The next is the resource. Since the design uses a lot of hinges, levers and styling blocks, they all fail sooner or later. The service life of multi-link suspension parts is 100 thousand kilometers. As for the beam, it is practically eternal. The design is much more reliable and does not require expensive maintenance. The maximum that needs to be replaced is the shock absorbers. They "walk" on our roads for about 80 thousand kilometers. The multi-link suspension requires more attention when driving over bumps. If the car begins to emit knocks in the front or rear, it is worth inspecting the condition of the levers and styling blocks. If there are any backlash and free play, they should be replaced.

The cost of the new levers on the 124th Mercedes is $ 120 per wheel. Despite the great age and low cost of the car, spare parts for it have not become cheaper. The same goes for other machines that use this type of suspension. If you need a lift or a viewing hole. Usually such machines are repaired at service centers. And these are additional costs.

Can you identify the problem yourself?

If you notice characteristic knocks while driving, the suspension may need to be repaired. To find out the exact reason, you need a viewing pit or overpass. If it is a front suspension, inspect the condition It has a boot. If it's cracked, an urgent replacement is needed. Otherwise, all the dirt will get inside and you will have to buy a new CV joint assembly.

Check for play in the steering rods. Inspect the shock absorbers. If there are streaks on them, most likely, the sound comes from them. This means that the valve inside the shock absorber is punctured and the stem moves randomly. The silent blocks of the levers and the anti-roll bar should also not have any backlash. Inspecting the rear suspension should begin with the shock absorbers. Next, we check the thrust. Often, elements are damaged in the area of ​​contact with the exhaust pipe.

Pay special attention to this place. If the muffler hits the body, there are characteristic impact marks, it is worth replacing its pillow. In most cases, the problem disappears. After examining the condition of the suspension, summarize which elements are out of order and need to be replaced. In the absence of experience, it is recommended to contact the service.

Conclusion

So, we found out the features of the multi-link suspension. As you can see, it has many disadvantages. But its main advantage is comfort. The way this car drives cannot be compared to anything else. It is also more agile. If there is a choice - a beam or a multi-link - it is worth starting from the budget. The last suspension should only be taken if you are willing to spend at least $ 400 to service it.