Bushings, also known as car bushes, are small, tubular-shaped blobs of polyurethane or rubber compound that play an important part in the steering and suspension setup of vehicles. They are installed on steering and suspension joints to control movement, reduce noise and vibrations, absorb bumps, and reduce friction.
They operate as vibration isolators, improving driver and passenger comfort. It is critical to inspect and replace worn bushings on a regular basis. 

 

 

Function

Car Bushings reduce friction and wear, absorb vibrations, provide support and stability, and compensate for misalignment. These functions are crucial for maintaining the smooth and efficient operation of various vehicle components, particularly in the suspension system.

  • Reduce Friction: In moving parts in a car's components, including suspension systems, bushings operate as a barrier, providing a layer of material between these parts and reducing wear and friction. The components' ability to slide smoothly against one another allows for longer component life and less power loss.
  • Absorb Vibrations: In order to keep vibrations from spreading to other areas of the car, bushings absorb and dampen them. A smoother and more comfortable ride is the outcome, particularly with suspension systems.
  • Provide Support: By keeping parts in place and limiting excessive movement and misalignment, bushings offer support and stability. They distribute the loads, maintaining accurate alignment and lessening system stress. 
  • Compensation for Misalignment: Certain types of bushings, like spherical bushings, can compensate for minor misalignments between components. They allow for angular movement, ensuring smooth operation even when parts are not perfectly aligned.

 

Types

Several types of vehicle bushes exist in a car's suspension system, including control arm bushings, leaf spring bushings, shock absorber bushings, steering rack bushings, and more broadly, stabilizer bar bushings.

  • Control Arm Bushings: Most cars use one or two control arms per wheel, with each arm housing two bushings. Control arm bushings connect the control arm and the frame or subframe of the vehicle, which allow for the controlled movement of the control arms while maintaining stability and proper alignment of the wheels.
  • Leaf Spring Bushings: Leaf springs are commonly used in the rear suspension of heavy-load bearing vehicles, such as trucks. These bushings support the weight of the vehicle and control the ride height, which also keep the tires in level contact with the ground.
  • Shock absorber Bushings: Shock absorber bushings, also known as suspension bushings are located on the suspension and steering joints, allowing for the smooth vehicle’s movement. They help absorb the shocks and vibrations caused by uneven road surfaces and bumps.
  • Steering Rack Bushings: A steering rack is a component that enables the rotational movement of the wheel when the steering wheel is turned. Steering rack bushings stabilize the steering rack while allowing for the vibration and road shocks absorption. 
  • Stabilizer Bar Bushings: Stabilizer bar bushings, also known as sway bar bushings are located underneath the sway bar or anti-roll bar of the vehicle. They prevent excessive vehicle rolling from side to side, caused by a worn or loose stabilizer bar, as the driver turns. 

 

Failure of Bushing

These parts are something like cartilage inside a car and can get worn just like one. The time it had been used and the condition of the road dealt with the lifespan of a bushing. Age, how much friction it has faced, and exposure to pollutants can also shorten its durability.

Symptoms of Failure

When bushings fail or develop problems, several symptoms may manifest, indicating the need for inspection and potential replacement. These symptoms include:

  • Unstable Braking: Although the bushings are not included directly in the vehicle’s braking system, bad or worn bushings can affect the oscillation of the control arm during breaking, which results in unstable and inconsistent braking performance.
  • Loose Steering: Worn or failed bushings can cause excess and inconsistent movements, particularly in the steering system where steering may not work properly(reduced responsiveness) or lean to one side. This can affect the overall vehicle’s steering, resulting in a serious wheel vibration, while in motion.
  • Uneven Tire Wear: When suspension or control arm bushings begin to wear or fail, they can cause wheel misalignment, leading to premature tire wear on the affected wheels.
  • Increased Noise: If the bushing is worn, the driver may hear squeaking or clunking sounds, particularly when going over bumps or turning the steering wheel. Failed bushings can result in excessive noise and vibration, making for an uncomfortable driving experience.

 

 

Tests

CTR offers a comprehensive range of verification tests for bushing - rubber material tensile/compression test, and rheometer.