ASE A5 Brakes Practice Test

51. A vehicle with a Hydroboost brake system has reduced braking performance. Which of the these could be the cause?

  • A. Low manifold vacuum.
  • B. A faulty vacuum check valve.
  • C. A clogged inlet valve.
  • D. A faulty power steering pump.


Answer A is wrong. Hydroboost brake units use power steering pressure instead of engine vacuum for brake assist.

Answer B is wrong. The vacuum check valve controls the flow of vacuum to a vacuum power booster.

Answer C is wrong. A clogged inlet valve blocks or slows the airflow into a vacuum booster.

Answer D is correct. The power steering pump produces pressure for the Hydroboost brake assist unit.

52. Which of the following input sensors are used by the traction and stability control systems?

  • A. Yaw Rate Sensor
  • B. Steering Angle Sensor
  • C. Wheel Speed Sensor
  • D. All of the above.


Answer A is wrong. The Yaw Rate sensor senses vehicle rotational speed around its vertical axis and informs the system when a vehicle is about to fishtail or roll sideways.

Answer B is wrong. The SAS Steering Angle sensor indicates the turning angle of the steering wheel.

Answer C is wrong. The wheel speed sensors indicate wheel speed to the control module.

Answer D is correct. They are sensor inputs for the ESP electronic stability program.

53. A technician is lubricating rubber brake components while performing a brake job. Technician A says to use a high-temperature silicon-based lubricant. Technician B says to use a petroleum-based lubricant. Who is correct?

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


Answer A is correct. Use a high-temperature silicon-based lubricant that does not contain petroleum.

Answer B is wrong. Petroleum-based products can cause swelling resulting in brake unit failure.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

54. A technician is testing a vehicle with a vacuum assist brake booster. After pumping the brake pedal several times and starting the engine, the pedal drops toward the floor about ¼ of an inch. Which of the following statements is correct?

  • A. This is normal.
  • B. The brake booster is faulty.
  • C. The master cylinder is faulty.
  • D. There is air in the brake system.


Answer A is correct. This is normal.

Answer B is wrong. Typically a loss of vacuum or a faulty brake booster results in a hard brake pedal.

Answer C is .wrong A faulty master cylinder usually results in a soft brake pedal that fades to the floor.

Answer D is wrong. Air in the system results in a soft pedal.

55. The front brake pads on a vehicle with a quick take-up master cylinder need replacement. They were recently replaced. Technician A says this is a low drag brake system. Technician B says the master cylinder quick take-up valve could be sticking. Who is correct?

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


Answer A is wrong. Both technicians are correct. This type of master cylinder is used with low drag brake calipers. It is distinguishable by a large diameter piston, and primary low pressure bore located at the back or push rod end of the master cylinder.

Answer B is wrong. The quick take up master cylinder provides more brake fluid volume to take up the additional space between the pads and the rotor. They are fuel-efficient.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.