What causes suspension damage

In this brief article, we will discuss the factors that cause suspension damage and ways to effectively prevent these damages.

What causes Suspension Damage?

The vehicle suspension is damaged due to the following reasons:

  • Bad Road surfaces
  • Salt-Spray from the road
  • Weathering and cracking of Rubber
  • Fatigue
  • Impact due to rocks Stone and road debris
  • Lack of lubrication

Bad Road Surfaces

It may sound ironic that the suspension’s very job is to deal with bad roads. But this is the very factor that determines a suspension system’s life. It may be noted that the exact same vehicle produced to the exact same specifications in probably the same model year, end up replacing suspension part at very different points in time. The difference here is the usage pattern. While one owner uses his car as a daily driver on smooth roads with a high percentage of highway driving, the other owner of the vehicle with identical spec and model might be using it daily over rural roads that are badly maintained.

The owner of the car going over rural roads would probably get his suspension replaced at 30-40k miles, while the other highway-driver owner would not see suspension failures until maybe 90K miles.

Salt-Spray from the road

Car owners who drive in the ‘Salt-Belt’ states of the U.S. or any other country region that sees a lot of snowfall would see the early onset of rust, especially in the underbody area. In Snowy areas, the roads are often ‘Salted’ to clear the ice, so that the roads are safer with more traction in the winter times. The resulting mixture of melted snow, dirt and salt form a deadly sludge that causes very quick rust. The dirt and stones scratch the metal surface of the suspension arms and wear out the protective coating that was done by the car manufacturer. The salt in the mixture goes into these scratched and exposed surfaces to accelerate the onset of rust. In this manner, the suspension, being fully exposed to road dirt all the time, would be the first of the components that start rusting underneath the car.

Weathering and cracking of Rubber

Most suspension arms are connected through the use of either ball-joints or Rubber bushings. Rubber degrades progressively with exposure to UV rays and sunlight. Also, the rubber is put to work most of the life of the vehicle since the suspension is nearly never stationary. At any given point in time, as long as the car moves, it would cause the suspension joints to see relative movement. Therefore the rubber undergoes fatigue, or gradual degradation where the elasticity is lost over time. Once the modelcular bonds holding the rubber in one piece starts to break down, cracks form, leading to the complete failure at some later point.

Fatigue

Fatigue is a phenomenon where the component’s material gets “Tired” or Fatigued. Suspension components are almost always made of some metallic alloy. Metals (or for that matter any structural material) have a property of elastic strength, due to which they are able to endure impact. During impact, like due to road bumps or potholes or any features, the suspension arm undergoes a certain amount of bending. In springs, the compression is very clear and visible, in suspension arms, it probably might not be that much apparent. Every material has a fatigue limit, or in other words, a fixed number of cycles for which the material has been bent within its elastic limit (Elastic limit means that the component bounces back to its original shape). Beyond that, the component, once bent, would be permanently deformed and hence failed.

Impact due to rocks Stone and road debris

In general, if the suspension sees more stones, gravel and rocks hitting underneath, it would be more prone to failure. ‘This could happen due to many reasons. It could be that the vehicle is being used more on loose off-road-type surfaces than on normal asphalt roads. If this is the case, then the stones hitting the lower suspension arms would cause the factory surface protection to wear out and expose the bare metal surface of the suspension arms. If the stones were big enough, the impact would sometimes even cause bending of the control arms made of sheet metal. The suspension arms who’s metal is exposed tend to rust quicker.

Lack of lubrication

In many cases, suspension joints are sliding joints, for eg. ball-joints, where a socket slides over a ball, to provide a swivel movement. This type of joint functions only when it is sufficiently lubricated. Many times, the ball-joint is serviceable, or the joint is enclosed, but has an inlet to pump grease into the joint and provide lubrication to the sliding surfaces. 

In other cases, the ball-joint is a ‘sealed-type’ meaning that the lubrication has been filled at the factory and cannot be replenished. Such types of joints are protected by an outed rubber boot that acts as the seal that prevents the lubrication from escaping. Once the rubber boot fails, it lets the lubrication escape, thus leading to the ultimate failure of the joint.

Ways to prevent suspension damage

The ways to prevent suspension damage are:

  • Driving carefully over rough patches and bad roads
  • Regular lubrication of the serviceable joints in the suspension at the manufacturer-recommended intervals
  • Replacement of rubber joints at the recommended intervals
  • Re-Tightening of the suspension and subframe joints at the recommended intervals
  • Underbody corrosion protection coating

Conclusion

In this brief article, we have discussed the factors that cause suspension damage and ways to effectively prevent these damages.

In case of any queries or comments, please feel free to ask.

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