One of the most pressing problems of Russian car owners is often a failed suspension, for which it is worth saying “thank you” to bad roads. In most cases, after such trips, urgent intervention in the "inside" of the car is required due to incomprehensible knocks. One of the most probable reasons is the failed silent block. This, of course, is not the most pleasant thing that can happen to a car, but it is quite fixable.
So, what is it - the silent block? What is it for, why does it fail? And most importantly - which one to buy silent blocks: polyurethane or rubber?
Purpose and causes of breakdowns
In fact, the silent block is a connecting element between the individual parts of the suspension. It is intended to eliminate vibrations and give the car softness and stability.
The silent block design is a hinge of two metal bushings and either a polyurethane or rubber insert, the function of which is to absorb shock bumps. The main reason for the failure of a part is, as a rule, a breakdown of the rubber or polyurethane part - it is it that is more susceptible to aging, wear and deformation more than other components. The most negative impact on the silent blocks is caused by chemical and temperature influences, which reduce the life of the part by several times and, as a result, lead to the need for its regular replacement.
How to check the silent blocks?
The average life of silent blocks averages 100,000 kilometers. However, taking into account Russian roads and conditions, it is advisable to carry out their diagnostics twice as often - every 50 thousand kilometers. To determine whether the silent block is worn out or not is quite simple - you need to listen to the car. Deteriorated response to steering, too heavy a move, delayed steering, are clear signs that the joints will have to be changed. To make sure that a replacement is necessary, it is advisable to conduct diagnostics in a car service.
Visual inspection is carried out at the inspection pit by checking the silent block cleaned of dirt. Rubber or polyurethane bushings must not be damaged or torn. An indirect evidence of a malfunction of such a detail is a change in the alignment, if previously it was correct. In the presence of breaks of silent blocks, the levers can be a little, but go to the sides.
It is also advisable to check the play and, if the parameter is excessive, replace parts.
Untimely replacement of faulty silent blocks can cause the car to move to the side at high speed. Uneven tire wear may also indicate a malfunction. They can cause destruction of the mounting seats of the hinges, which may lead to the need to replace the front suspension arm.
What set of silent blocks to choose for replacement?
Just a few years ago, the question of which particular silent blocks to put did not even arise among car owners. All quietly acquired rubber and used them. However, recently, with the development of technology, a novelty has appeared - silent blocks are polyurethane. Reviews about them are positive. Many install them on their cars. What are their advantages and what is to choose a silent block - polyurethane or rubber? How are the details different from each other?
Polyurethane bushings: pros and cons
Benefits:
- Increased resistance to high loads.
- Compared with rubber counterparts, they have a longer service life.
- Increase stiffness and tightness of the suspension. Often this improves the maneuverability and controllability of the car.
- Resistant to temperatures and their differences. Rubber analogues are afraid of too high and low temperatures, while polyurethane does not dry out and does not crack.
- Resistant to aggressive environments, not afraid of the effects of petroleum products, reagents and other substances that destructively affect rubber.
Cons of polyurethane bushings:
- The increased rigidity. Not for every car too stiff suspension is good. Often this can only lead to discomfort in management.
- The increased stiffness of the suspension can lead to deformation of body parts, shock absorbers and the chassis. Silent blocks are polyurethane, reviews confirm this, sometimes contribute to the fact that shock absorbers flow or the lower rack mount breaks.
- Price. Compared with rubber analogues, polyurethane ones cost 4-5 times more, while you can buy non-original spare parts, the service life of which is in great question.
- Despite the high strength of polyurethane and its ability to withstand high loads, it can not withstand twisting, which is one of the main reasons for its deformation.
Three reasons to buy rubber silent blocks
- Habit. Most cars come from the factory with rubber parts; during operation, there is no trouble with them.
- Softness. Polyurethane bushings are more rigid, so for lovers of a soft and comfortable ride they will not work.
- Cost. The price of rubber silent blocks is much lower than polyurethane.
Three reasons to purchase polyurethane bushings
- Reliability. High strength, minimum operating requirements, high resistance to various influences.
- Long term of operation.
- Security. Maneuverability, dynamics and controllability of the car improves.
How to choose silent blocks for a car?
The suspension design of modern machine models includes rubber-metal hinges, referred to as silent blocks and located both on the rear and front wheel levers, subframe mounts, jet rods and stabilizers.
All of the above VAZ auto parts are consumables and require regular replacement depending on the mileage of the car. With the condition of using the classic silent block on domestic roads, it is able to serve at least 100,000 kilometers, but it is advisable to conduct a technical inspection and diagnostics every 30 thousand. You can determine if the hinges require replacement by the following criteria:
- On visual inspection, deformation of the elastic insert is noticeable.
- The car creaks when swinging in different directions.
- While driving, the sound of a suspension is heard in the cabin.
- Rubber wears unevenly.
If any of the above symptoms appear and a complete diagnosis is made, the silent blocks change if necessary. This can be done both independently and in a car service, where there is the necessary equipment and a lift or a viewing hole. With an independent change, you can encounter certain difficulties, especially if there are no suitable tools and there are no skills on how to press in the silent block.
In the automotive parts markets you can find Nissan polyurethane bushings from different manufacturers. Despite the fact that most of the details are original, you can encounter a low-quality fake, the installation of which will lead to its change after a while.
As already mentioned, silent blocks are polyurethane, reviews of which are mostly positive, were able to gain popularity among car owners. Such products are characterized by increased strength and less subject to wear, although the pros and cons, of course, must be taken into account.
The long service life of silent blocks is explained by their ability to maintain firmness, elasticity and strength even under the influence of large loads and deformations. In addition, polyurethane is resistant to temperature effects without loss of physico-chemical properties.
The design features of the polymer several times increase the service life of polyurethane bushings, in contrast to the classic rubber counterparts. They are able to withstand harsh operating conditions for a long time without losing their characteristics.
Rubber hinges are less expensive than those made of polymers, but their service life is many times shorter.
The highest quality silent blocks and other suspension parts are manufactured by HANSE, TOCHKA OPORY and LYNX: products are made only from high quality materials using innovative technologies. They are distinguished by a long service life, strength, resistance to mechanical wear, uneven physical loads and temperature extremes ranging from -45 to +50 degrees.
What you need to know before buying parts
Depending on the specific make and model of the car, the dimensions of the silent blocks will also change. Therefore, in order to purchase a suitable part, it is necessary not only to know the year of manufacture of the car, but also the number of its body. In addition, the dimensions of the silent blocks, their inner and outer diameter and the length of the part play an important role.
Almost all parameters can be found without removing the spare part, but problems with the inner diameter can occur. The fact is that many parts have special bushings designed to reduce wear. For this reason, when choosing silent blocks, these errors are taken into account without fail.
Before choosing which polyurethane bushings are better, it is advisable to familiarize yourself with the manufacturing companies involved in their production. The most high-quality auto parts of VAZ and other car brands are produced by such companies as Lemforder, Mood, Corteko and Boge.
Installation and fitting
The silent block is inserted into the lever with certain efforts. It’s just that it’s impossible to establish a place — it requires the use of a special press available in a car service or a set of tools with which you can perform the procedure yourself.
To understand how to press in the silent block, you need to get minimal information about its design and acquire the necessary tools. The procedure itself is simple: first the old part is removed, the seat on the lever is cleaned and a new one is pressed in. It is not difficult to remove polyurethane, but you will have to work on the metal part.
To remove the polyurethane saylentblok of the front lever, it is necessary to carefully cut the metal part with a jigsaw and knock it out with a hammer. Throwing it away is not worth it - it may be needed later.
The seat is cleaned of sharp edges and burrs. The surface should be perfectly smooth and even. If the new silent block does not have an external metal cage, then it is lubricated with either special grease or a soap solution.
After that, they begin to press-in the silent block. The easiest option is to use a sledgehammer to drive the sleeve into place. However, this method requires skill and accuracy: you can easily damage not only the silent block of the beam, for example, but also the beam itself.
What is the difference between polyurethane and rubber?
Many motorists install bushings, stabilizers and rubber bushings on their cars. This is explained by the low price of such products and an acceptable service life, provided that all requirements are met. Rubber parts can last about 50-100 thousand kilometers if the car is not involved in racing and is not used for driving on dirt roads or off-road.
Polyurethane bushings, the pros and cons of which are known to many motorists, are able to withstand more severe operating conditions. For this reason, they are often used in cars participating in races, when ride comfort is pushed to the last place for the sake of car handling. The service life of such parts is several times longer, since the polymer is less susceptible to wear and abrasion, unlike rubber.
Silent blocks polyurethane reviews do not always get positive - you can meet car owners who are unhappy with the installation of such parts. As a rule, the cause of possible malfunctions is the acquisition of low-quality goods in an attempt to save money. In addition, spare parts may not be installed correctly without contacting a service center.
As a result of improper installation, polyurethane parts require replacement after 20-50 thousand kilometers, while their average life is 80-100 thousand.
The polyurethane suspension also has its weak points. The density of the polymer increases with decreasing ambient temperature below 20 degrees, which leads to its deformation with increasing loads. Silent blocks and stabilizer bushings will work properly only if the entire suspension is in good condition. In the presence of any malfunctions, the service life of the parts is reduced several times.
Installation of polyurethane parts is much more complicated than rubber parts, which is associated with their increased strength. In addition, their price is slightly higher than those made from rubber.
Long-term conditions for silent blocks
Parts made of polyurethane will last a long time, subject to certain requirements:
- Acquisition of high quality products only from reliable manufacturers.
- Carrying out overhaul of the suspension simultaneously with the change of silent blocks.
- Installation of new parts using special equipment.
- The polyurethane support is treated with silicone grease or lithol.
- Regular inspection of the suspension and its parts.
- Car operation at an ambient temperature of at least -20 degrees.
Products made from polyurethane
The technology for the production of automotive parts from rubber and polyurethane is significantly different. For this reason, parts made of polymer can be of various shapes. Special processing of the material improves the strength of the connection with metal parts, which improves the performance of finished parts. Products made from polyurethane are widely used in the automotive industry.
The cost of such products is several times higher than rubber analogues, due to the complexity and resource intensity of the production technology. For this reason, polymer parts cannot universally replace rubber, despite this, polyurethane is quite widely used in areas where the quality of materials is required.
Professional tuning of car suspension requires the use of parts that are reliable, high quality and wear resistance. Of course, changing the suspension of race cars or SUVs requires only parts of increased strength and reliability, but polyurethane products can also be used in the suspension of a conventional car.
The suspension made of polyurethane improves the controllability of the car and ride comfort. High level of wear resistance, resistance to temperature changes positively affect the dynamics of the car, making it more convenient when driving. The parts made of polymer do not lose strength at low temperatures, are more resistant to wear and tear under prolonged loads.
Polyurethane bushings, unlike rubber, are resistant to chemicals used on roads, dirt and dust, which significantly prolongs the life of the car.
The behavior of the car on the road is greatly improved through the use of polyurethane parts. Silent blocks allow to reduce the deformation of the suspension and eliminate the effect of "squeezing", which is typical for parts made of rubber. Simply put, the car suspension will always work in only one mode, without experiencing unnecessary loads. Properly selected and installed parts made of polyurethane reduce noise and vibration, absorb shock much better than rubber counterparts.