ASE A5 Brakes Practice Test

11. Which of the following brake fluids is silicon-based?

  • A. Dot 5.1
  • B. Dot 3
  • C. Dot 4
  • D. Dot 5

11.

Answer A is wrong. DOT 5.1 is a different chemistry; it's a non-silicon-based alternative that should not be mixed with DOT 5 brake fluid.

Answer B is wrong. Most of today's vehicles use DOT 3 or DOT 4, a glycol (Polyalkylene Glycol Ether) based brake fluid.

Answer C is wrong. Dot 5 is silicon-based, and DOT 4 is a common glycol-based brake fluid.

Answer D is correct. Silicon-based fluid (DOT 5) is usually found in special applications like show cars because it doesn't damage painted surfaces like its glycol counterpart.

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12. A vehicle has a low brake pedal that slowly fades to the floorboard, causing the vehicle to creep forward at stoplights. An initial inspection indicates that the master cylinder reservoir is full, and no external leaks exist. Which of the following is causing this condition?

  • A. Contaminated brake fluid.
  • B. Leaking master cylinder cup seals.
  • C. Vacuum brake booster failure.
  • D. A faulty metering valve.

12.

Answer A is wrong. Old and contaminated brake fluid has likely absorbed moisture and has a lower boiling point. Therefore, a brake fluid flush will be necessary.

Answer B is correct. The brake pedal will fade to the floor as fluid pressure bypasses the internal cup seals. This pressure loss can cause the vehicle to creep forward in gear.

Answer C is wrong. A faulty brake booster results in no or little brake assist, resulting in a hard brake pedal.

Answer D is wrong. Vehicles with front disc rear drum brakes have metering valves. Metering valves delay pressure to the front calipers long enough for the system to overcome rear drum spring pressure and achieve balanced braking.

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13. The front of a passenger vehicle has a growling sound that increases in intensity while making left-hand turns. The MOST likely cause of this sound is:

  • A. Excessive rotor lateral run out.
  • B. A faulty left-front wheel bearing.
  • C. A worn outer CV-Joint.
  • D. A faulty right-front wheel bearing.

13.

Answer A is wrong. A warped rotor results in a pulsating brake pedal (front) and felt in the driver's seat (rear).

Answer B is wrong. A faulty left front wheel bearing is loudest while making right-hand turns.

Answer C is wrong. A worn outer CV joint clicks while cornering.

Answer D is correct. The vehicle's weight and inertia push on the right front wheel bearing during a left-hand turn. A faulty right front wheel bearing is loudest while making a left-hand turn.

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14. Technician A says accumulators are found only on non-integral ABS systems. Technician B says some integral ABS units contain high-pressure accumulators that must be discharged before repair. Who is correct?

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

14.

Answer A is wrong. Accumulators are found on integral and non-integral ABS systems.

Answer B is correct. High-pressure units can be dangerous and must be discharged before removal. Always check with the manufacturer's procedures before disassembling an ABS unit.

Answer C is wrong. Technician B is correct.

Answer D is wrong. Technician B is correct.

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15. The master cylinder reservoir cap gasket is swollen and deformed. The cap fits tight, and there are no external leaks found. Technician A says this could be caused by contaminated brake fluid. Technician B says brake fluid is hygroscopic and readily absorbs moisture from the air. Who is correct?

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

15.

Answer A is wrong. Petroleum products are particularly damaging to rubber brake components. Inspect the gasket for damage and the fluid for contamination. A flush will be necessary if the gasket's seal is missing or broken and the brake fluid is contaminated.

Answer B is wrong. Brake fluid is hygroscopic and readily absorbs moisture from the air. The reservoir cap gasket functions as a flexible seal to prevent contamination of the brake fluid. Fluid would appear on the reservoir's body if the cap seal leaked.

Answer C is correct. Most of today's vehicles have composite plastic reservoirs with a screw-on type cap. Reservoir caps have a rubber gasket between the cap and the reservoir.

Answer D is wrong. The gasket flexes inward and prevents air from entering the system as reservoir levels drop.

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