ASE Practice Test (A5: Brakes) 1 — Questions and Answers

Question 1: Which of the following is caused by a power assist brake booster push rod that is too short?

Brake light is illuminated
Excessive brake drag
Brake system to be inoperative
Excessive brake pedal travel (Correct answer)

Correct answer: Excessive brake pedal travel

If the power assist brake booster push rod is too short, there will be an excessive gap between the push rod and the master cylinder piston when the brake pedal is at rest. This means the brake pedal must travel a greater distance to bridge this gap and begin engaging the master cylinder, resulting in a symptom of excessive brake pedal travel.

Question 2: Which of the following indicates a spongy brake pedal on a car with 4-wheel disc brakes and a longer than normal travel?

Caliper piston seized
Parking brake out of adjustment
Air in the hydraulic system (Correct answer)
A faulty power booster

Correct answer: Air in the hydraulic system

A spongy brake pedal with longer than normal travel is a classic symptom of air trapped within the hydraulic brake system. Unlike incompressible brake fluid, air bubbles compress when the pedal is applied, absorbing some of the pedal force before it can be fully transmitted to the calipers. This compression results in a soft, spongy feel and requires increased pedal travel to achieve effective braking.

Question 3: A vacuum brake booster is installed on a vehicle. It doesn't have power assist until the engine has been running for a minute, after which it functions normally. What is the most probable cause?

Adjusted brake pedal push rod is too short
Front brake disc is worn
Engine requires a tune-up to produce a higher vacuum at idle speed
Defective check valve (Correct answer)

Correct answer: Defective check valve

The most probable cause is a defective check valve in the vacuum brake booster. The check valve is designed to maintain vacuum within the booster even when the engine is off, providing immediate power assist upon startup. If the check valve is faulty and leaks, the vacuum bleeds off, requiring the engine to run for a period to re-establish sufficient vacuum in the booster before power assist becomes available.

Question 4: During braking, the brake pedal on a vehicle with power-assisted disc/drum brakes gently glides to the floor. Which of these possibly be the source of the problem?

A leaking power brake booster diaphragm
A leaking brake booster check valve
An internal leak in the combination valve
An internal master cylinder leak (Correct answer)

Correct answer: An internal master cylinder leak

When the brake pedal gently glides to the floor, it typically indicates an internal leak within the master cylinder. This occurs when the piston seals (cups) are worn or damaged, allowing brake fluid to bypass the piston instead of being forced into the brake lines to actuate the calipers and wheel cylinders. Consequently, hydraulic pressure cannot be maintained, and the pedal slowly loses resistance.

Question 5: What may be the cause of a spongy brake pedal?

Frozen caliper piston
Air in hydraulic system (Correct answer)
ABS Diagnostic Trouble Code set
Defective metering valve.

Correct answer: Air in hydraulic system

A spongy brake pedal is a classic symptom of air trapped within the hydraulic brake system. Unlike brake fluid, which is incompressible, air bubbles compress when the brake pedal is applied. This compression absorbs some of the force intended for the brakes, resulting in a soft, yielding pedal feel and reduced braking efficiency.

Question 6: The ABS (antilock brake system) amber light does not go off after the engine is started. Technician X says a parking brake not fully released could be the cause. Technician Y says when this happens the brakes will operate like a normal non-ABS brake system. Who is right?

X only
Y only (Correct answer)
Both X and Y
Neither X nor Y

Correct answer: Y only

Technician Y is correct because when the ABS warning light illuminates, it indicates a fault within the anti-lock braking system, causing it to disable itself. In such cases, the vehicle's brakes will still function, but they will operate as a conventional, non-ABS system, meaning the wheels can lock up under hard braking. Technician X is incorrect; a parking brake not fully released typically illuminates a separate red brake warning light, not the amber ABS warning light.

Question 7: Even though all of the adjustments have been done according to the specifications, the brake pedal begins to feel spongy and low. What might be the source of the issue?

Binding pedal linkage
Dented brake line
Plugged compensating port
Weak hydraulic hose (Correct answer)

Correct answer: Weak hydraulic hose

A weak or deteriorated hydraulic brake hose can cause a spongy and low brake pedal, even after proper adjustments. When brake pressure is applied, a compromised hose can expand or balloon outwards, absorbing some of the hydraulic force instead of fully transmitting it to the brake calipers or wheel cylinders. This expansion results in a soft, spongy pedal feel and increased pedal travel.

Question 8: When light pedal pressure is applied to a vehicle with disc/drum brakes, the front brakes grab quickly. It's possible that this is the result of a failed:

residual check valve
metering valve (Correct answer)
proportioning valve
pressure differential valve

Correct answer: metering valve

The metering valve in a disc/drum brake system is designed to slightly delay the application of the front disc brakes. This delay allows the rear drum brake shoes to overcome their return spring tension and make contact with the drums first, ensuring balanced braking. If the metering valve fails or sticks open, the front disc brakes will engage immediately and more aggressively than the rear, causing the front brakes to grab quickly with light pedal pressure.

Question 9: Which of the conditions listed below can cause brake pedal fade?

Air in the hydraulic system
Seized wheel cylinder piston
Brake drum machined beyond its limit (Correct answer)
Leakage past the master cylinder cups

Correct answer: Brake drum machined beyond its limit

Brake pedal fade, characterized by a loss of braking effectiveness, can be caused by a brake drum machined beyond its maximum allowable limit. When a drum is excessively thin, it has less material to absorb and dissipate heat generated during braking. This leads to rapid overheating and distortion of the drum, significantly reducing friction between the shoes and drum, and resulting in severe brake fade.

Question 10: The axle grease soaked the rear brake linings, and there's still a lot of lining left on them. What is the proper procedure for servicing these brakes?

Wash in hot, soapy water and dry.
Repair leak and replace brake linings (Correct answer)
Clean with approved cleaner and reuse
Replace the brake linings

Correct answer: Repair leak and replace brake linings

If axle grease has soaked into the rear brake linings, the proper procedure is to repair the source of the leak and replace the brake linings. Grease impregnates the porous friction material, making it impossible to clean effectively and drastically reducing its coefficient of friction. Attempting to clean and reuse contaminated linings would result in severely compromised and unsafe braking performance, necessitating their replacement along with fixing the leak.

Question 11: The absence of free play on a vehicle's brake pedal can lead to:

Low brake pedal
Pressure build-up and dragging brakes (Correct answer)
Fluid leaking beyond the primary piston cups
Spongy brake pedal

Correct answer: Pressure build-up and dragging brakes

The absence of free play in a vehicle's brake pedal means the master cylinder push rod is constantly applying slight pressure to the piston. This prevents the master cylinder's compensating port from fully opening, which is necessary to relieve residual pressure in the brake lines. Consequently, pressure builds up in the hydraulic system, causing the brakes to drag, overheat, and wear prematurely.

Question 12: On a car with single piston floating caliper disc brakes, the disc brake pad between the caliper piston and the rotor is badly worn. The other brake pad is slightly worn. Technician X says excessive rotor run out could be the cause. Technician Y says insufficient clearance between the pads and caliper slider could be the cause. Who is right?

Both X and Y
Neither X nor Y
X only
Y only (Correct answer)

Correct answer: Y only

Technician Y is correct because insufficient clearance between the pads and caliper slider, or seized caliper slide pins, prevents the floating caliper from moving freely. This causes the piston to push only its inner pad against the rotor effectively, while the outer pad receives minimal force, leading to severe wear on the piston-side pad and only slight wear on the outer pad. Technician X is incorrect; excessive rotor runout typically causes brake pulsation and potentially tapered pad wear, but not this specific pattern of uneven wear between the inner and outer pads.

Question 13: When the front brakes of a car with a drum/disc system are applied lightly, the front brakes lock up. This problem could be caused by a bad:

Proportioning valve
Pressure differential switch
Metering valve (Correct answer)
Residual check valve

Correct answer: Metering valve

In a disc/drum brake system, the metering valve is designed to slightly delay the application of the front disc brakes. This delay allows the rear drum brake shoes to overcome their return springs and make contact with the drums, ensuring balanced braking. If the metering valve is faulty or stuck open, the front disc brakes will engage too quickly and aggressively, causing the front wheels to lock up prematurely, even with light pedal pressure.

Question 14: All of these steps must be completed when removing the master cylinder, except:

Drain the master cylinder (Correct answer)
Disconnect the float level sensor
Plug the ends of the brake lines to prevent fluid loss
Vacuum boost pressure with power brakes

Correct answer: Drain the master cylinder

Draining the master cylinder completely is not a mandatory step for its removal. While siphoning fluid from the reservoir is often done to minimize spills, the master cylinder itself doesn't need to be fully drained. The other options, such as disconnecting the float level sensor, plugging brake lines to prevent fluid loss and contamination, and relieving vacuum boost pressure, are all essential preparatory steps for safe and clean master cylinder removal.

Question 15: When the brakes are applied, the front of a car with a disc/drum system vibrates. Which of these possibly be the source of the problem?

Binding caliper slides
Unequal tire pressure
A frozen caliper piston
Excessive rotor runout (Correct answer)

Correct answer: Excessive rotor runout

When the front of a car vibrates during braking, a common cause is excessive rotor runout. Rotor runout, or warp, means the brake rotor is not perfectly flat or concentric. As the brake pads clamp down on this uneven surface, it causes the caliper pistons to move in and out with each rotation, resulting in a noticeable pulsation or vibration felt through the brake pedal and steering wheel.

Question 16: The race (cup) of a bearing can be dented after it has been shock loaded. What is the type of this sort of bearing failure?

Fluting
Brinelling (Correct answer)
Spalling
Arcing

Correct answer: Brinelling

Brinelling is the specific type of bearing failure characterized by indentations or dents in the bearing race, often caused by static overload or severe shock loading. These permanent depressions occur when the rolling elements are forced into the race material, leaving marks that resemble the hardness test indentations from which the term "Brinell" is derived.

Question 17: Brakes on an older vehicle with a quick take up valve in the master cylinder are being bled. Technician X believes that you must depress the quick take up valve. Technician Y believes that the brakes can’t be bled. Who is correct?

Neither technician (Correct answer)
Both technicians
Technician X
Technician Y

Correct answer: Neither technician

A quick take-up valve is an internal master cylinder component designed to rapidly move brake shoes/pads and then reduce fluid volume, not to be manually depressed. Brakes can be bled normally even with this valve present, as its function does not impede the bleeding process. Therefore, both technicians are incorrect in their beliefs.

Question 18: After machining, the thickness of a front disc brake rotor is slightly less than the minimum thickness specification. The technician should be able to:

machine the other front rotor to the same thickness
reuse the rotor
replace the rotor (Correct answer)
apply a non-directional finish to the rotor

Correct answer: replace the rotor

Disc brake rotors have a critical minimum thickness specification to ensure safe and effective braking. Machining a rotor below this minimum thickness compromises its structural integrity, making it prone to warping, cracking, or overheating, which can lead to brake failure. For safety reasons, any rotor that falls below the minimum thickness after machining must be replaced.

Question 19: Technician X says a defective wheel or axle bearing can make a growling or rumbling noise. Technician Y says a defective wheel displays looseness or excessive play in the steering wheel especially while driving over rough road surfaces. Who is right?

Both X and Y (Correct answer)
Neither X nor Y
X only
Y only

Correct answer: Both X and Y

Technician X is correct because a worn or defective wheel or axle bearing commonly produces a growling or rumbling noise, especially noticeable during turns or at certain speeds. Technician Y is also correct; excessive play in a wheel bearing can cause the wheel to move improperly, leading to noticeable looseness or wandering in the steering, particularly over rough road surfaces.

Question 20: Which of these will be the result of a short power assist brake booster push rod?

Inoperative brake system
Excessive brake drag
Illuminated brake light
Excessive brake pedal travel (Correct answer)

Correct answer: Excessive brake pedal travel

The power assist brake booster push rod connects the brake pedal to the master cylinder. If this rod is too short, it creates excessive free play between the pedal and the master cylinder piston. This means the brake pedal must travel a greater distance before it begins to actuate the master cylinder, resulting in excessive brake pedal travel.

Question 21: A hydraulic brake line has sprung a leak. Which of these repairs is correct?

Replace the leaking line with double-flared seamless aluminum tubing.
Cut out the bad section and replace with single-flared steel tubing using flare nuts and unions.
Replace the leaking line with double-flared steel tubing. (Correct answer)
Cut out the bad section and replace with new steel tubing using compression fittings.

Correct answer: Replace the leaking line with double-flared steel tubing.

Hydraulic brake lines operate under high pressure and require robust, leak-proof construction. Replacing a leaking line with double-flared steel tubing is the correct repair because steel tubing provides the necessary strength and corrosion resistance. Double flares create a secure, high-pressure seal, which is essential for brake system safety and performance.

Question 22: The front wheel bearings are being adjusted. Technician X says you torque the adjusting nut to a specified torque and back off the nut till it lines up with the hole and install the cotter pin. Technician Y says backing off the castle nut will cause the bearing to overheat. Who is right?

Both X and Y
Neither X nor Y
X only (Correct answer)
Y only

Correct answer: X only

Technician X correctly describes the standard procedure for adjusting tapered roller wheel bearings: torque to seat, then back off slightly to align for the cotter pin. This ensures proper preload without overtightening. Technician Y is incorrect; backing off the castle nut is necessary to prevent excessive preload, which would cause the bearing to overheat and fail, not backing it off.

Question 23: When a vehicle's brakes are applied, erratic brake pulling happens. All of these could cause this problem EXCEPT:

Flare nuts
Double wall steel tubing
Double wall copper tubing
High-pressure rubber tubing (Correct answer)

Correct answer: High-pressure rubber tubing

Erratic brake pulling is caused by an imbalance in braking force between wheels. While a collapsed internal lining in a flexible brake hose (high-pressure rubber tubing) is a very common cause of brake pulling, the question asks for the EXCEPT case. Issues with flare nuts, double wall steel tubing (e.g., restrictions), or the improper use of double wall copper tubing (leading to failure) could all cause pulling. Given the options, the question likely implies that a properly functioning high-pressure rubber tubing itself is not the cause, unlike potential issues with the other components.

Question 24: After each application, the drag on a vehicle's drum brakes increases until they lock up. For a brief period, bleeding the system restores normal operation; however, drag increases until the brakes lock up again. Which of these possibly be the source of the problem?

Weak brake shoe return springs
Incorrect brake shoe adjustment
A seized wheel caliper
A failed master cylinder (Correct answer)

Correct answer: A failed master cylinder

The symptoms of brakes dragging and locking up after repeated applications, with temporary relief after bleeding, are classic signs of a failed master cylinder. Specifically, a blocked compensating port within the master cylinder prevents fluid from returning to the reservoir when the pedal is released. This traps residual pressure in the brake lines, causing the brakes to progressively apply and eventually lock up.

Question 25: The ABS (antilock brake system) and TRACTION OFF indicator lights remain ON with the engine running. Technician X says to check for ABS or TCS (traction control system) diagnostic trouble codes. Technician Y says you can check for ABS or TCS blink codes by connecting two pins of the DLC (Data Link Connector). Who is right?

Both X and Y (Correct answer)
Neither X nor Y
X only
Y only

Correct answer: Both X and Y

Technician X is correct because illuminated ABS and TRACTION OFF lights indicate a system fault, requiring diagnostic trouble codes (DTCs) to be retrieved with a scan tool. Technician Y is also correct; on some older or simpler systems, 'blink codes' can be accessed by shorting specific pins on the Data Link Connector (DLC), causing the warning light to flash a sequence corresponding to the fault.

Question 26: The engine has brake fluid in it, which you notice. This leakage could be caused by:

Defective vacuum hose to the brake booster
Partially restricted air cleaner element
Defective PCV valve with excessive restriction
Defective one-way check valve in booster vacuum hose (Correct answer)

Correct answer: Defective one-way check valve in booster vacuum hose

The brake booster uses engine vacuum, and a one-way check valve in its vacuum hose maintains vacuum. If this check valve fails, it can allow brake fluid (from a leaking master cylinder) to be drawn into the vacuum hose and then into the engine's intake manifold. This results in brake fluid entering the engine, often indicated by a burning smell or smoke from the exhaust.

Question 27: With the brakes applied, the pedal moves down slightly when the engine is started on a vehicle with power brakes. Technician X says that a leaking power brake booster diaphragm could be the cause. Technician Y says that a stuck-closed brake booster vacuum check valve could be the cause. Who is right?

Both X and Y
Neither X nor Y (Correct answer)
X only
Y only

Correct answer: Neither X nor Y

When the brake pedal moves down slightly upon starting the engine, it indicates that the power brake booster is correctly engaging and providing vacuum assist. Technician X is incorrect because a leaking booster diaphragm would cause a hard pedal or loss of assist. Technician Y is also incorrect; a stuck-closed vacuum check valve would prevent vacuum from reaching the booster, also resulting in a hard pedal, not a slight drop.

Question 28: A vehicle with disc/drum brakes requires excessive brake pedal effort to stop. The brake pedal is firm when applied. While starting the engine with the brakes applied, the pedal does not go down slightly. Technician X says excessive brake pedal freeplay could be the cause. Technician Y says air trapped in the hydraulic system could be the cause. Who is right?

Both X and Y
Neither X nor Y (Correct answer)
X only
Y only

Correct answer: Neither X nor Y

The symptoms describe a firm, hard brake pedal requiring excessive effort to stop, and the pedal does not drop when the engine starts, indicating a lack of power assist. Technician X is incorrect; excessive brake pedal freeplay would result in a low pedal. Technician Y is also incorrect; air in the hydraulic system would cause a spongy or soft pedal. The issue points to a problem with the power brake booster or its vacuum supply.

Question 29: All of these components are included in brake system except:

High-pressure rubber tubing
Double wall steel tubing
Double wall copper tubing (Correct answer)
Flare nuts

Correct answer: Double wall copper tubing

Brake systems require strong, durable lines to withstand high pressures and resist damage. Double wall steel tubing is the standard for hard brake lines, and high-pressure rubber tubing is used for flexible hoses, connected by flare nuts. Double wall copper tubing is generally not used for brake lines because copper is softer than steel, prone to work hardening and cracking, and does not meet safety standards for this critical application.

Question 30: The following would cause a low brake pedal, EXCEPT:

Low brake fluid
Seized caliper piston (Correct answer)
Brake adjustment
Loose wheel bearing

Correct answer: Seized caliper piston

A low brake pedal typically indicates a problem where brake fluid isn't effectively building pressure or is being lost. Low fluid, improper brake adjustment, or a loose wheel bearing can all contribute to a low pedal. A seized caliper piston, however, would prevent the brake pads from engaging properly on that wheel, leading to reduced braking force on that side, but it would not directly cause a low brake pedal.

ASE Practice Test (A5: Brakes) 1

Which of the following is caused by a power assist brake booster push rod that is too short?