If an air brake equipped commercial vehicle begins to 'fishtail' or 'jackknife' when braking, particularly on slippery surfaces, which component's malfunction or improper adjustment could be a significant contributing factor?

Question: If an air brake equipped commercial vehicle begins to 'fishtail' or 'jackknife' when braking, particularly on slippery surfaces, which component's malfunction or improper adjustment could be a significant contributing factor?

Answer options:

• The air dryer is not purging effectively.
• The governor cut-out pressure is too high. ✅ Uneven or excessive slack adjuster settings between drive axles or tractor/trailer.
• A faulty low air pressure warning light.

Correct answer: Uneven or excessive slack adjuster settings between drive axles or tractor/trailer.

Explanation: Uneven brake adjustment, particularly between axles or sides of the vehicle, can lead to imbalanced braking forces. If brakes on one side or axle grab harder or sooner, it can cause the vehicle to pull, swerve, or 'fishtail' during braking, especially on low-traction surfaces.