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Difficulty: MediumSuspension Systems

A fleet mechanic inspects a cargo van that maintains correct factory ride height when loaded, yet suffers from rapid tire bounce and uncontrolled wheel hop after driving over uneven pavement. Which suspension component is failing to perform its primary function?

  1. A
    Leaf spring assembly
  2. B
    Upper spring shackle
  3. Hydraulic shock absorberAnswer
  4. D
    Rubber jounce bumper

Answer

The hydraulic shock absorber is failing to perform its primary function of damping axle oscillations.
The hydraulic shock absorber is designed to control and dampen spring oscillation and axle hop by forcing fluid through calibrated internal valves. Because the vehicle does not sag under load, the springs are functioning, but the inability to stop repeated bouncing demonstrates a loss of hydraulic damping.

Step-by-Step Solution

1
Evaluate the static vs. dynamic symptoms described in the scenario.
The vehicle maintains proper static ride height under load, confirming that the load-supporting components are structurally sound.
Suspension springs (such as leaf or coil springs) are responsible for supporting vehicle weight and establishing ride height.
2
Differentiate between weight support and motion damping to identify the faulty part.
Excessive tire bounce and wheel hop indicate a lack of kinetic energy dissipation after encountering bumps.
Shock absorbers convert the kinetic energy of oscillating springs into thermal energy through hydraulic fluid restriction, keeping tires planted on the road.

Key Concept

Functional separation between suspension springs (weight support and ride height) and shock absorbers (oscillation damping).
Estimated Time:1m 0s
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Topics

Suspension Systems

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