What is a silentblock? Why should it be changed?
Don’t forget to watch the video attached to the post.
Let’s imagine the situation, you come in for diagnosis and the technician tells you that it’s time to change the silentblocks. But you, as a beginner car enthusiast, do not understand the meaning of these words and do not even know what they are. Then this article will be useful for you, from it you will learn what is a silentblock and what it is for, as well as why you need to change it.
What is a silentblock and what does it do?
A silentblock, or in other words, a rubber-metal joint, is two metal sleeves with a rubber insert between them. The silent blocks serve to connect the suspension components, and due to the elastic insertion between the bushings (rubber or polyurethane) dampens the vibrations transmitted from one unit to another. It carries the heaviest loads, because it must withstand the deformation that the vehicle’s suspension receives.
Where is the silentblock installed? Silent blocks are found both in the front suspension of the car, to attach the arms, stabilizer bar, reaction rods, as well as to attach the rod in the rear suspension. Silentblocks are also used to attach shock absorbers, transmission, engine. And all these rubber-metal joints need constant and timely inspection.
How do you check the silent blocks?
How do you know when it’s time to change the silentblocks? Usually, silentblocks last up to 100,000 miles, but in Russian conditions with our roads not of the best quality, you should do an inspection of the silentblocks every 50,000 km. mileage.
You can tell if a suspension silentblock is worn out by your senses. If the car’s handling is worse or the steering response is “sluggish” with a long delay, this is a sure sign of a worn bushing. But to be more confident, you should contact an auto service or make an inspection of rubber-metal joints yourself.
A visual inspection of the bushing is as follows: go to a pit or a trestle, and look visually at the clean of dirt bushing. There should be no cracks or tears in the rubber part. It is advisable to imagine what a new bushing looks like. An indirect indication could be a cambered camber, if it is known to have been correct before. When the silentblocks tear, the arms become slightly crooked.
You should also check the backlash in the silent blocks and if excessive, also replace them as a matter of urgency.
What does untimely replacement of the silentblocks lead to? If they are badly worn, they can cause the car to drift at speed. I.e. the car will sort of bounce from side to side. One more unpleasant sign of rubber-metal joints wear is uneven wear of tires. Actually, uneven wear of tires indicates incorrect camber, which in turn may hint at the car’s suspension malfunction.
Do not hesitate to replace the silentblocks because they can destroy the hinge seats, in which case, for example, the complete front suspension arm will have to be replaced.
The biggest difficulty encountered when replacing old bushings with new ones is the difficulty of pressing them in. This will require special tools, mandrels, and a press to press them in and out of the lever. Of course, you can use Russian ingenuity, and just pick up a suitable mandrel from a piece of pipe, and then press the new silentblock with a “sledgehammer”. This requires a certain amount of skill and accuracy, as it is possible to damage the rubber insert.
If you decide to replace the bushings yourself, first assess the complexity of the repair from this video clip. And then decide if you can replace the silentblocks with your own hands or it is better to apply to a car service.
As for replacing the silentblocks in the nodes fixing the engine, gearbox, then you should seek help from professional car masters. It is necessary to do this because their replacement in these nodes is a very time-consuming operation, and to do it you need excellent knowledge of the basics of the car and experience in its repair. Otherwise, you might just “mess up,” and then replacing the old silentblocks will cost you a pretty penny.
Remember, after replacing the silent blocks in the suspension with new ones, you should restore the angles of wheel convergence and camber. By the way, this operation should be done at any intervention and repair of your car suspension.
Polyurethane or rubber silentblocks, which is better?
If your car has in the suspension, any rubber bushings and silent blocks, which can be replaced with polyurethane parts, you will only improve the performance of the suspension and its work. Polyurethane сайлентблоки parts will last at least 5 times longer than rubber parts.
The only disadvantage of polyurethane is its higher cost compared to rubber products (more than 5 times), but you can save on replacement.
Polyurethane silent blocks improve the car’s behavior on the road by reducing unwanted deformation in the suspension and eliminating the “squeeze” effect common to rubber parts. This means that the suspension always performs as designed. Correctly installed and selected polyurethane parts always work better, absorbing shocks, vibration and reducing noise in comparison with rubber.
To summarize, if you want to improve the drivability of the car and adjust the suspension to your own driving style – then the polyurethane silentblocks are just what you need. If you drive quietly from one point to another on a daily basis, then the choice is in favor of conventional rubber silentblocks.
Why do automobiles need silent blocks and how to choose them correctly?
A fair number of car owners, even as car owners, have heard of silentblocks, but do not know their exact function and location.
Cars are built in such a way that even insignificant elements play a very important role. This means that all components need to be monitored to ensure they are in good working order. Among them are the silent blocks.
They also have another name. They are rubber-metal joints. But the silentblock or just a silent has become more familiar and common designation of this element.
Function and purpose
To begin with, we need to understand what silent blocks are and why they are needed in a car. Silent blocks or rubber-metal joints are a special small device that is responsible for reducing vibrations and noise transmitted from the suspension during its operation to the body. It is largely due to them the driver and passengers feel comfortable in the car when driving on the roads.
Structurally, the silent is made in the form of a pair of bushings made of metal, and between them is set an insert of elastic material. This is often polyurethane or rubber, which are also often compared and try to determine the best solution. This is to the question of what car silent blocks look like.
When it comes to what a silentblock is in any car, it can be characterized as a mediator between a suspension element and a rigid body. Suspension elements include levers, springs, subframes and shock absorbers.
It’s easy enough to understand how this silentblock works if you use visualization. Just imagine that another metal element is attached to the body. During driving, there will be constant contact between the two metal surfaces. And now make a spacer between the metal in the form of an elastic material. Immediately disappear extraneous sounds, increased driving comfort.
Now you understand what car silent blocks affect. They are a means to reduce the vibrations of the suspension. Although on some cars, silent blocks can also be found on the engine and various moving parts of the suspension. There, they perform the same functions, that is, they dampen vibrations and connect different parts to each other.
The same type of joints found in the suspension are also found in gearboxes, powertrain mounts, shock absorbers, stabilizers, etc.
The silent blocks are a consumable component. They are constantly exposed to high loads, that is why their service life is limited. It is usually recommended to replace them at intervals of about 50,000 km.
Initially, the joint may seem a small and insignificant part of the car. But if you study the functions and features of the element, the opinion completely changes to the opposite. It is an extremely important component of the entire suspension. If the silent is in a worn condition, the handling of the vehicle will immediately deteriorate. Especially strongly disobedience of the machine is manifested when driving at high speeds. With wear there is a characteristic creak, the car begins to roll, and in the steering wheel there is a backlash.
Components and Location
The classic silentblock is in the form of two metal bushings connected to each other and an insert based on an elastic material. But modern rubber-metal joints have become more diverse, their appearance has changed, and there are distinctive features in the design.
Depending on where the silent joint is mounted, it may be made with a metal sleeve on the outside, or it may be completely rubber.
There is also a difference in the structure of the different elements. There are solid bushings, ribbed bushings, vibration-absorbing bushings, etc. Parts where the rubber insert has vibration damping are found on the engines of foreign cars. These elements absorb vibrations from the engine to the body.
The most frequent and largest number of silent blocks are in the front suspension of the car, as well as in the structure of the rear suspension. To be more specific, we are talking about the levers. They serve to hold the moving components of the car’s suspension. Front joints are installed on the front levers, which explains their name. They carry the heaviest load, because they are responsible for the moving and pivoting components of the vehicle. The silent, which is located here, requires careful monitoring and mandatory periodic replacement as it wears.
In the rear suspension of the car also does not do without silentblocks. They are mainly located on the shock absorber mounts and on the reaction rods. Wherever there is a load on the running gear from the body, or moving and stationary elements are connected, the rubber-metal joints are used.
Motorists often wonder how many silent blocks there are in a particular component. The number of rubber-metal joints largely depends on the specific suspension component, as well as the decisions of automakers. You can tell exactly how many silent blocks there are in the front or rear suspension with the help of the owner’s manual. Typically, the upper and lower arms have 2 hinges per arm, just like the rear suspension design. Some cars have 3 silent joints on the lower arm.
If you add up, it turns out over 8-10 silent blocks only in the front suspension, and about 12-16 in the rear suspension design. But it is impossible to answer unequivocally, as the number of these parts depends on the particular car.
Rubber vs. polyurethane
Since rubber-metal joints need to be replaced at certain intervals, motorists are faced with the natural question of choosing new elements.
With the development of the automobile industry, more modern and higher quality parts appear. They include the bushings. Therefore, the car owner has to choose which silentblocks are better to use for his vehicle. It is necessary to choose between two variants. These parts are based on rubber and polyurethane.
Rubber silent blocks are considered the simplest. It’s a classic option that has been around since the advent of the concept of rubber-metal joints. Hence the name itself. The gradual abandonment of rubber has led to the fact that it is no longer entirely fair to call silent blocks rubber-metal joints.
Regardless of the name, rubber bushings are made using rubber. This is a cheap enough material to make the part cheap. But the low price is the main argument in favor of rubber. Several weight disadvantages speak against it at once:
- poor service life;
- Even new silents can squeak, creating discomfort in the car;
- Negative environmental influences quickly render rubber unusable;
- susceptibility to high and low temperatures;
- poor resistance to moisture and precipitation;
- tendency to shrivel and crumble over time.
For cheap and old domestic cars are suitable and rubber joints. Although even on such cars, experts do not advise to put low-quality parts. It is better to give preference to polyurethane analogs.
If we talk about polyurethane elements, they are significantly superior to their rubber competitors. And there is practically no competition here. Polyurethane is characterized by higher performance characteristics. Due to the use of such material it was possible to significantly increase the level of comfort and quality of suspension. This has a positive effect on the behavior of vehicles.
Among the advantages of polyurethane as a basis for the manufacture of silentblocks are the following points:
- Service life. It significantly exceeds the period during which rubber elements retain their serviceability. Tests show the fivefold superiority of polyurethane over conventional rubber, i.e. rubber.
- Car behavior. With polyurethane suspension elements the car behaves much better on the road, enters corners with more confidence and doesn’t have the squeezing effects which are typical for rubber. Deformation processes in the suspension are also prevented. All this allows you to drive the car with comfort.
- Absorption. Noise, vibration and sound absorption efficiency is at the highest level here.
- Controllability. A car with polyurethane joints steers much easier and more confidently. Those who have personally experienced the work of the two types of silent blocks can confirm it. The feeling of driving a vehicle on different silent blocks is significantly different.
But here, too, it is not without disadvantages. The only disadvantage of polyurethane is its cost. Silents based on this material are much more expensive than their rubber counterparts.
But the price should not become a reason to refuse to use polyurethane. Moreover, the difference in cost will not be particularly tangible. If you initially install a higher quality and more durable silentblocks, the interval between replacements will significantly increase. Over the life of one polyurethane silentblock, about 2-3 rubber parts have to be replaced. This keeps the cost issue to a minimum.
We should not forget the popular saying that the stingy always pay twice. Here and in this situation, it is right and rational to give preference to polyurethane rather than rubber.
Causes of failure
Under normal circumstances, the silentblock will gradually wear out due to natural causes. This element has a limited lifespan, which is expended depending on operating conditions and the degree of exposure to internal and external negative factors.
But wear and tear can occur before its due date. If in a normal situation, replacement is performed approximately every 50,000 kilometers, in certain situations, the resource is used up faster. There are several main reasons for premature failure of silent blocks. You need to know them in order to understand when it is time to buy new elements.
- Tightening the mounting bolts. The reassembly procedure after replacing the bushings means that the bolts must be tightened. Many people do it while the car is still suspended or standing on jacks. But according to the rules it must be done only after lowering the car to the ground. Even experienced mechanics forget about this rule, which leads to negative consequences and soon failure of suspension elements.
- Seat. For each silentblock, the car design provides a socket. And the element must be installed there as accurately as possible. If you do not adhere to strict rules and violate installation recommendations, even the most expensive and high-quality joints will not last long. You will have to replace them.
- Long service life. You do not need to wait until the suspension starts to break, or the silentblock finally ruptures. You need to monitor the condition and behavior of the vehicle. At the first sign of wear, you need to proceed with replacement.
- Chemicals. It is not at all necessary for the silent to come into contact with aggressive chemicals, various solvents and alkalis. Sometimes contact with ordinary motor oil is enough. Oil can corrode rubber, but does not particularly affect polyurethane. In any case, this is a direct road to the replacement of the element.
Practice clearly shows that, if properly installed, quality silentblocks are able to fully work out the declared resource. There are no serious problems with them during the operational period.
Therefore, when choosing new parts, you should pay attention not only to the manufacturing material, but also to who exactly is manufacturing the joint.
Motorists want to know which silentblocks are really the best, and which company’s products deserve attention. Those who have taken silent blocks from different brands could clearly feel the difference between the leading manufacturers and little-known companies.
If the driver bought an item and noticed that the behavior of the car has changed for the worse, it is better to refuse further use of joints of this brand.
Take the best of the current assortment, and you can’t go wrong. And the best does not mean the most expensive. When choosing, be guided by what kind of car you’re buying silentblocks for.
Considering all the current offers on the market, you can make a kind of rating of the leading manufacturers of automobile silentblocks. What is the most interesting, it is represented by both foreign and domestic brands.
- BelMag. A large Russian manufacturer, which is engaged in the manufacture of silent blocks for domestic vehicles. The history of the company has almost 30 years. They offer parts for vehicles of domestic assembly, including not only VAZ, but also Nissan, Renault, etc. BelMag carries out a full cylinder assembly cycle, which is due to the presence of large-scale production facilities. The products are considered of sufficient quality, as evidenced by the numerous awards in the Russian and international competitions. Products of this brand are available in all regions. In its favor also speaks an adequate price.
- Trialli. A company from Italy, which is also ready to offer bushings for Russian-made and assembled cars. Since 2005, their dealer network began working in Russia. Consumers note the durability and adequate price of Italian silentblocks. The quality may not be perfect, but they easily work for a few seasons in our operating conditions. The only problem is that sometimes it is difficult to find the Italian company’s joints.
- Stellox. A Chinese company that is ready to offer its own silents for rear and front arms for a wide range of car models. It is a worthy competitor for the leading parts manufacturers. Stellox products sell well in Russia. These silentblocks are recommended for Asian passenger cars. But it is important to note that the silentblocks from Stellox do not like too bad roads.
- CTR. Another brand from Asia. But this time we are talking about Korea. Its production was launched back in 1960. Koreans carefully control all stages of production, which allows achieving a high level of quality. These silentblocks are used from the factory on different models of Ford, Kia, Hyundai and General Motors. A direct confirmation of the high quality. Of the disadvantages one can highlight the small range on the domestic market.
- RBI. A leading manufacturer of auto parts from Thailand. Produces parts for a large number of Japanese companies, as well as working with some European car manufacturers. The whole range is divided into two brands. These are Ritco and RBI. The first parts are designed for commercial cars, and bushings for cars should look for under the RBI brand. The products have a democratic price and are rarely counterfeited. The disadvantages include a limited range, as well as not the longest service life.
- Febi. It is a German company with a huge history and no less impressive range of products. One of the world leaders, which deservedly occupies a high place in international rankings. Parts Febi are sold in more than 120 countries, there are branches and subsidiaries in many countries. Their silentblocks are factory produced for Mercedes and DAF. At the domestic market the brand has gained a reputation as a manufacturer of high-quality parts, including the silentblocks. The main disadvantage is the extremely high popularity, due to which the market is constantly seeing fakes.
- Optimal. Another manufacturer of silentblocks from Germany. The company has been existing for over 40 years. These products are of high quality, meeting the most stringent standards. Not for nothing that such companies as Opel, General Motors and Ford recognize them. In addition, Optimal supplies its bushings to the production conveyors of Volkswagen, Renault.
- Nissan, BMW, Chrysler, Peugeot, and others. Some bushings are not adapted to Russian conditions, and can therefore wear out before their lifespan.
- Lemforder. But nevertheless, the best manufacturer of automobile silentblocks is considered to be Lemforder, which is a part of the big concern ZF. This is a German brand, which appeared back in 1947. The assortment includes more than 13,000 different silentblocks, which are suitable for installation on different makes and models of cars. Products of this brand are used in plants of leading automobile companies. The advantages are high quality, durability and reliability. The minus is due to the pluses, because the products have high price tags, plus you can often come across fakes.
It is hardly necessary to doubt the choice between dubious silentblocks of unknown origin and the products of the leading manufacturers. The only question is not to buy a fake.
Each manufacturer offers its own methods of protection against counterfeits. It is advisable for motorists themselves to contact only verified and certified sellers, always inquire about the documents for the sold goods, and check the package itself and the silentblock contained in it.
Although silent blocks are extremely compact in size, it is difficult to overestimate their importance. It is one of the key components of the suspension, providing the necessary level of comfort and safety in the movement of the vehicle. This is why extreme care needs to be taken when selecting and replacing bushings.