ASE A5 Brakes Practice Test

41. A vehicle with a vacuum brake booster has a hard pedal with little stopping power. Technician A says a kink in the check valve's hose results in this condition. Technician B says a vacuum booster needs at least 12" Hg of vacuum to operate correctly. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

41.

Answer A is correct. An inoperative brake booster, a faulty check valve, or a kink in its hose results in a hard brake pedal.

Answer B is wrong. A brake booster needs more vacuum, between 17-21 Hg, to function correctly.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

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42. A vehicle has a low spongy brake pedal. Which of these is LEAST likely to result in this condition?

  • A. Loose wheel bearings.
  • B. Contaminated brake fluid.
  • C. Worn brake pads.
  • D. Air in the hydraulic system.

42.

Answer A is wrong. Loose and worn wheel bearings result in a low spongy brake pedal due to excessive movement.

Answer B is wrong. Contaminated brake fluid can damage seals and cause a low spongy brake pedal.

Answer C is correct. Low brake pads result in a warning clip squeal or an illuminated brake pad warning light.

Answer D is wrong. Aerated fluid results in a spongy pedal.

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43. Technician A says passive permanent magnet ABS wheel speed sensors produce an AC voltage signal. Technician B says anti-lock brake, electronic traction control, and electronic stability control systems use input from the wheel speed sensors. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

43.

Answer A is wrong. The signal is sent to the electronic controller for anti-skid, stability, and traction control.

Answer B is wrong. The signal is sent to the electronic controller for (ABS) anti-lock brake, (TCS) traction control system, and (ESC) electronic stability control.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

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44. The brakes of a four-wheel disc brake system are self-applying and locking up after only a few miles of travel. Which of the following is the MOST likely cause of this condition?

  • A. A blocked master cylinder replenishing port.
  • B. A blocked master cylinder vent port.
  • C. Worn master cylinder cup seals.
  • D. Low intake manifold vacuum.

44.

Answer A is wrong. A blocked master cylinder replenishing port would result in a vacuum forming behind the primary or secondary pistons.

Answer B is correct. Blocking the vent port can lead to pressure buildup and brake lockup. The vent or compensation port allows for the expansion of brake fluid. Brake fluid expands as its temperature rises from normal braking. The excessive pressure will cause the brake units to self-apply.

Answer C is wrong. Worn master cylinder cup seals result in a fading or sinking brake pedal.

Answer D is wrong. Low intake manifold pressure will result in a hard brake pedal in a vacuum brake assist system.

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45. A vehicle has erratic braking and a longer than average stopping distance. A scan tool indicates a faulty power brake booster pressure sensor. Technician A says a faulty brake booster pressure sensor will lower brake fluid level in the brake master cylinder reservoir. Technician B says the power brake booster pressure sensor measures brake booster (vacuum) pressure. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

45.

Answer A is wrong. A faulty brake booster pressure sensor will set a code (P0555) and illuminate the check engine or brake warning light when a fault is found in the sensor or its circuit. It will not result in low brake fluid.

Answer B is correct. The sensor converts vacuum pressure in the power brake booster to a voltage signal for the ECM. A faulty sensor will result in erratic braking and a spongy/hard brake pedal with long stopping distances.

Answer C is wrong. Remember to inspect the wiring and connections for looseness and wear before replacing the sensor.

Answer D is wrong. Technician B is correct.

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