Mixed Deck — All ASE A5 Topics Flashcards

After installing a new front brake hose, what check should be made before returning the vehicle to service?

Answer: Turn the steering wheel fully left and right and check for hose binding, stretching, or contact

Steering and suspension movement must not stretch, kink or rub the hose. Turning lock to lock confirms there is enough slack and clearance.

A brake pushrod gauge is used when installing a master cylinder on a power booster. What does the technician compare with this tool?

Answer: Booster pushrod protrusion against the depth of the master cylinder piston recess

The gauge checks that the booster pushrod length matches the master cylinder piston depth so the piston ends up with the correct clearance.

What causes the red brake warning lamp to light through a pressure differential switch?

Answer: A drop in hydraulic pressure in one circuit shifts the valve piston into contact with the switch

If one circuit loses pressure, the higher pressure in the other circuit pushes the differential piston toward the low-pressure side. The piston closes the switch and lights the warning lamp.

A vehicle with a conventional dual-diagonal split hydraulic system is being bled, and the manufacturer gives no special sequence. Which wheel should be bled first?

Answer: The wheel farthest from the master cylinder

Bleeding normally starts at the wheel with the longest line run from the master cylinder, which is usually the right rear. Air is then pushed out of the longest circuits first.

On a vehicle with ABS, air remains in the hydraulic control unit after the wheel circuits have been conventionally bled, and the pedal is still soft. What is the best next step?

Answer: Use a scan tool to run the ABS automated bleed procedure, which cycles the valves and pump, and then bleed the wheels again

Many ABS units hold air in internal passages that conventional bleeding cannot reach. A scan tool bleed cycles the valves and pump so the air can be pushed out.

A technician is told that a customer previously topped off the reservoir of a vehicle with DOT 5 silicone fluid. The system is now to be serviced with DOT 3. What is the proper procedure?

Answer: Fully flush the system with the specified fluid and replace any contaminated seals and hoses as needed

Silicone DOT 5 does not mix with glycol-based DOT 3, so the system must be completely flushed. Seals that were exposed to the incompatible fluid may need replacement.

Which of the following is a safe fluid to use for cleaning hydraulic brake components such as a master cylinder bore or caliper pistons during service?

Answer: Denatured alcohol or clean brake fluid

Denatured alcohol and clean brake fluid will not harm rubber seals. Petroleum products cause the rubber to swell and fail.

A technician is performing a functional test of a vacuum power brake booster. With the engine off, the pedal is pumped several times to deplete the reserve vacuum, then held firmly while the engine is started. What should the technician expect from a good booster?

Answer: The pedal should drop slightly and then hold

When the engine starts, vacuum is applied to the booster and assists the pushrod, so the held pedal drops slightly. No movement indicates no vacuum assist.

A customer complains of a high-pitched squeal from the front brakes that occurs while driving and stops when the brake pedal is pressed lightly. What is the most likely cause?

Answer: Pad wear indicators contacting the rotors

A wear indicator tab on the pad touches the rotor when the lining is nearly worn out. It makes a squeal that often stops when brake pressure is applied.

Before measuring lateral runout of a front disc brake rotor with a dial indicator, what should the technician do first?

Answer: Make sure the wheel bearing has no excess play and the rotor is mounted correctly

Looseness in the wheel bearing or poor rotor mounting can give a false runout reading. The bearing and rotor mounting must be correct before measuring.

Before adjusting a rear parking brake cable on a vehicle with rear drum brakes, what should the technician verify first?

Answer: The rear service brakes are in good condition and properly adjusted

Parking brake cable adjustment compensates only for cable slack, so the shoes and self-adjusters must be in good order first to avoid a false adjustment.

Before disconnecting a brake line on an integral ABS with a high-pressure accumulator, what must be done first to relieve stored pressure?

Answer: Disconnect the wheel speed sensors and drive the vehicle

Accumulator pressure can reach roughly 2,000 psi or more. It is relieved by pumping the pedal with the ignition off until the pedal becomes firm.

After the parking brake lever is released, the rear wheels still drag and the rear brakes overheat. Which is the most likely cause?

Answer: A seized or corroded parking brake cable

A cable that is corroded or seized in its housing does not return fully, so the shoes or pads stay partly applied and the rear brakes drag.

What is the purpose of a residual pressure check valve in the master cylinder outlet for a drum brake circuit?

Answer: To hold slight pressure in the line so the wheel cylinder cups stay sealed and air is kept from entering

Residual check valves hold roughly 6–18 psi in drum brake lines, keeping the cup seals tight against the wheel cylinder bores and reducing air entry.

A vehicle has stability control codes and the warning light on after a wheel alignment that changed the steering wheel position. Which service is most likely required?

Answer: Calibrate or reset the steering angle sensor with a scan tool

The steering angle sensor zero point must match the straight-ahead position after an alignment or steering component service. A scan tool calibration relearns it.

A technician is replacing a section of steel brake line on a vehicle that uses SAE 45-degree flare fittings. Which type of flare should be formed on the tube end?

Answer: A double flare

SAE 45-degree brake fittings require a double flare. The doubled-over wall is stronger and resists splitting under high pressure.

A technician spins a wheel by hand with a digital multimeter on AC millivolts connected across a passive (variable-reluctance) wheel speed sensor. Which reading is expected from a good sensor?

Answer: An AC voltage that increases as the wheel is spun faster

A variable-reluctance sensor generates its own AC signal from the changing magnetic field as the tone ring teeth pass. Both amplitude and frequency rise with wheel speed.

A vehicle with rear drum brakes has a low brake pedal on the first application. The pedal rises and feels firm when it is pumped, and the fluid level and front brakes are normal. Which is the most likely cause?

Answer: An inoperative drum brake self-adjuster

Excessive shoe-to-drum clearance means the pedal must travel farther to take up the gap. Pumping the pedal closes that gap and brings the pedal up. A self-adjuster that doesn't work leaves the shoes too far from the drum.

A technician measures a brake drum and finds the friction surface is larger than the maximum diameter cast into the drum. What is the correct action?

Answer: Replace the drum

The cast discard diameter is the largest safe inside diameter. A drum beyond it has less metal to absorb heat and resist cracking, so it must be replaced.

A technician is pressure bleeding a brake system. Which of the following is the correct practice?

Answer: Pressurize the system to about 15 psi using an adapter that fits the master cylinder reservoir

Pressure bleeders typically run at roughly 10–25 psi through a proper reservoir adapter. Higher pressure risks damaging seals and the reservoir.