what they are and when to change them

A silent block It is literally a silent block. That is, a bushing that Helps mitigate parasitic vibrations. In the automotive world, its application is common in suspension systems. Although it may not seem like it, this component is very important. Thanks to it, any trip or simply the mere act of starting the car is infinitely more comfortable. At the dawn of the automotive industry, everything was noise and rattles.

A little history

It was Charles E. Sorensen, head of Ford Motor Company during its first four decades of history, who credited Walter Chrysler, founder of the company of the same name, as the striker of the silentblock. In his memoirs (1956) he says that, on March 10, 1932, Chrysler called Ford headquarters to show a new model of Plymouth with an interesting novelty.

“The most radical feature of his car was the novel suspension of its six-cylinder engine to reduce vibration. The motor It was supported on three points and rested on rubber supports. Noise and vibration were much less. There was still a lot of engine movement at idle, but under light load it was mitigated. Although it was a great success in the Plymouth, Henry Ford did not like it. For no reason given.”

Thus, Chrysler's novel engine mounting method was marketed as “Floatng Power” and was a success. That simple idea soon became a standard within the automotive industry. These rubber mounts are now also found on the doors, hinges, windshield, bumpers and headlights, all with the idea of eliminate squeaks and rattles. We can thank Walter Chrysler for a quieter way of life.

What are silent blocks

They consist of two metal sleeves, sandwiched one in the other, where between them there is a rubber insert. Silent blocks are used to connect parts of a vehicle suspension, softening the vibrations transmitted from one part to another while driving. In addition to the suspension, these rubber-metal joints (the silent blocks often referred to) are mounted on other systems of the car, such as the engine or gearbox.

Silent blocks have to withstand an enormous load to fulfill their function. This is why their condition must be checked from time to time, replacing them with new ones whenever they have suffered significant wear. It is advisable take a look at them every 50,000 kilometers. It must be taken into account that the silent blocks allow a certain amount of movement inside them, and this is what causes wear.

Silent blocks are usually shaped like a cylinder, with flexible material inside a metal casing.

This movement allows the different parts that make up the suspension to move freely. For example, when we drive on the road and go over a large pothole, the transmission of noise and small vibrations through the vehicle's chassis is minimized. These are its main advantages, in addition to require little or no lubrication. The only maintenance they need is to take them to the trash when they have reached the end of their useful life.

To determine the condition of the rubber gaskets, we can do a simple check. Push the car from each corner and see if you hear any metallic noise during rocking. If you don't hear any noise but the swaying is very pronounced, perhaps what you need is to replace the shock absorbers. In addition, we can check the silent blocks with our own eyes: If they are cracked or peeling, they must be replaced.

This seemingly minor detail greatly affects the health of our vehicle and its handling, especially at high speeds or on roads in poor condition. In addition, a worn bushing causes very unpleasant noises in the suspension. You may have ever pulled your car out of the garage and heard a noise like “clack” when turning the steering wheel. Think that the suspension also acts when steering, even with the car stationary.

As often happens within the world of mechanics, prolonging the agony of a worn part ends up leading to more serious breakdowns that will make our pockets bleed. The silent blocks can also deteriorate faster with the presence of oils, as well as with extreme temperatures. If the time has come to change them, there are bushings made with more rigid materials, such as polyurethane, whose durability is greater than those made of rubber.

How long do silent blocks last?

Like any other wearing part such as the clutch, brake pads and discs or tires, silent blocks lose effectiveness over kilometers and time. Under normal conditions (without passing over bumps as if we were fleeing from the police) they can fulfill their task adequately during 120,000 – 150,000 kilometers. Yes, they can last longer, but you will see how much you are willing to risk.

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