A driver operating a commercial vehicle equipped with hydraulic brakes approaches an exit ramp and discovers that pressing the brake pedal results in the pedal sinking directly to the floor with no deceleration. In what sequence should the driver perform the emergency actions to safely stop the vehicle?
- 1Downshift the transmission into a lower gear to harness engine compression braking.
- 2Pump the brake pedal rapidly to generate any remaining hydraulic pressure.
- 3Apply the parking brake gently while holding the release mechanism to modulate braking force.
- 4Steer into an open escape route or clear shoulder away from moving traffic to come to a halt.
Answer
The driver should first downshift to a lower gear, pump the brake pedal rapidly, apply the parking brake while holding the release control, and finally steer toward an open escape path or shoulder.
The established emergency sequence for hydraulic brake failure starts with downshifting to establish immediate engine braking, followed by pumping the brake pedal to build residual hydraulic pressure, modulating the independent parking brake to slow further, and finally guiding the vehicle into a clear escape area to stop safely.
Step-by-Step Solution
Key Concept
Standard chronological response sequence for hydraulic brake failure in commercial motor vehicles.
Estimated Time:45s