What causes suspension problems

In this brief article, we will discuss what the most common Suspension problems are, and what causes these problems.

Most common suspension Problems and What Causes these Problems

Shock absorber failure

  • Shock absorbers, otherwise known as Damper, could be termed as the most common among all vehicle suspension components with only very few exceptions
  • The Shock absorber’s job is to reduce the bounciness in the suspension that comes from the Spring by absorbing the vibrational energy via rebound and compression movement of Damping fluid 
  • A shock absorber involves a Piston Rod oscillating within a Damper Tube

Piston Failure:

  • The Piston and Damper inner Tube surface needs to provide a sealing effect while moving up and down, and thus diverting the damper oil to flow through the piston valves
  • The sealing effect between the piston and the damper inner tube is what ensures that suspension vibrations are damped
  • Over time, the piston and inner tube surface wear out and eventually the sealing effect between them is lost

Rod Seal Failure:

  • On the top of the tube is a Rod-guide seal between the Piston Rod and the Damper Tube. This is responsible for preventing the leakage of oil to the outside of the damper tube.
  • Over time and sometimes, due to excessive temperatures, this seal too can wear out
  • The result of the Rod-guide seal failing is that damper oil leakage and subsequent loss of damping effect

Suspension Bushing Failure

  • Suspension Arms are attached to the chassis, in almost every car, by means of a flexible Rubber/Polymer Joint called as a Bushing
  • The reason for this is to provide a restricted freedom of movement, and at the same time, provide isolation from road vibrations
  • Rubber bushings weather and crack over time by exposure to sunlight, varying temperatures, Dirt, Rain, salt from the road, etc.
  • Once the bushing Rubber cracks, the joint fails to restrict movement and leads to noises when the suspension arm contacts with either the subframe or the chassis

Spring Breakage

  • A Majority of cars have either Steel Coil Springs or Steel leaf springs as the main suspension element
  • A Spring’s main function is to support the suspension at its predetermined ride height and absorb loads coming from road unevenness
  • A Coil Spring or leaf spring works by combination of bending and twisting while the suspension goes into compression
  • The spring offers resistance to bending/twisting and thus gives the suspension its “Ride Rate” or “Stiffness”
  • Springs can undergo only a finite number of compression/expansion cycles after which they develop fatigue cracks
  • Once a crack is initiated, it ultimately leads to the spring breaking into 2 or more pieces when it is near the end of its life
  • In ordinary cars, Spring breakages could happen anywhere between 100K to 200K miles, depending on the type of vehicle and usage pattern
  • Springs that cover a higher percentage of their mileage in Off-Road situations tend to fail faster since the terrain is rough and the springs need to work harder.

Air Spring Failure

  • An increasing number of vehicles in the premium segment come with Air suspension as either standard or as an option
  • Like steel springs, Air Springs also have a finite life after which they tend to fail
  • The Air Spring is basically a rubber balloon that gets inflated using pressurized air from a compressor.
  • The walls of the air spring bellow are made of reinforced Rubber, quite similar to a Tire wall
  • As the suspension moves from rebound to compression, the walls of the air spring bellow stretch or contract under air pressure
  • This stretch and contraction leads to fatigue of the rubber material and subsequent cracking
  • The cracks widen and develop into holes through which air leaks out from the air spring

Rusting of Suspension Components

  • A vehicle’s underbody is subject to constant sprays of mud, water, stones, road debris, and in many cases, salt.
  • Regions that experience prolonged spells of snow and icy weather have Salt sprayed onto the road surface. This is done in order to melt ice and increase road grip for vehicle tires in view of safety.
  • Vehicles operating in such conditions often have, in effect, a combination of water, salt and mud, sprayed on their underbodies continuously.
  • These conditions are highly conducive for the initiation of rust in all the metallic suspension components
  • Vehicles that spend most of their mileage in snow belts tend to rust quicker especially at the components closer to the road surface, which is the suspension.
  • Rust eats away the metal and ultimately leads to breakage

Conclusion

In this brief article, we have discussed what the most common Suspension problems are, and what causes these problems.

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