Brake System Test

Technician A says that the tool shown above is used to adjust the brake shoes. Technician B says that the tool shown above is used to determine the inside diameter of the drum. Who is right?

.Technician A only

The diameter of drums mounted on the same axle should measure within how many thousands of an inch of one another?

0.010

When rough machining a brake drum, the depth of cut and spindle feed rate should be:

0.010-0.015-in. at high feed rate

Absorption of 3% moisture can reduce the boiling point of DOT 3 brake fluid by what percentage?

25%

When replacing disc brake pads, you must bottom the caliper piston in its bore to create room for the new pads. Which of the following is the proper procedure?

Connect a hose to the caliper bleeder screw and insert the other end of the hose into a suitable container, open the bleeder screw, then use a C-clamp or pliers to slowly bottom the piston in the caliper.

A wheel cylinder has been disassembled and corrosion and light scoring have been found in the bore. Technician A says the bore can be refinished using a small hone lubricated with cutting oil. Technician B says oversize pistons and cup seals can be installed if the hone removes too much material. Who is right?

Neither Technician A,Technician B

During routine vehicle maintenance, the fluid level in the master cylinder reservoir is checked. When the reservoir cap is removed, purple colored fluid is found in the reservoir. Technician A says that this means the fluid should be topped off with DOT 4, which has a higher boiling point than regular brake fluid. Technician B says that this means that the fluid is contaminated; all rubber parts in the system must be replaced and the system flushed. Who is right?

Neither Technician A,Technician B

Technician A says that DOT 5 brake fluid has a lower boiling point than DOT 4.Technician B says that DOT 4 brake fluid is silicone-based and should never be used in an ABS system. Who is right?

Neither Technician A,Technician B

Technician A says that RWAL ABS systems must be diagnosed using a scan tool. Technician B says that the ABS warning light will only come on when there is a fault in the system. Who is right?

Neither Technician A,Technician B

Technician A says that when a rotor is machined, an equal amount of material must always be removed from both sides. Technician B says that the minimum thickness dimension cast into the rotor is the dimension that the rotor can be machined to. Who is right?

Neither Technician A,Technician B

Technician A says the type of fitting shown above is common to all brake systems. Technician B says the flare shown was formed with an inverted flaring tool. Who is right?

Neither Technician A,Technician B

Two technicians are discussing brake bleeding procedures. Technician A says gravity bleeding is a relatively quick way to bleed a brake system. Technician B says silicone brake fluid cannot be gravity bled. Who is right?

Neither Technician A,Technician B

With foot pressure applied, the brake pedal on a vehicle with vacuum assisted power brakes moves down slightly when the engine is started. Technician A says that this condition can be caused by a leaking power brake booster diaphragm. Technician B says that the cause could be a faulty power brake booster check valve. Who is right?

Neither Technician A,Technician B

The front disc brake pads are being replaced on a vehicle with composite rotors. The left front rotor is scored below the 'machine to' but not the 'discard' thickness. The right front rotor has minor heat checks but otherwise checks out OK. If cast rotors are the only available replacements, which of the following is the proper course of action?

Replace both rotors.

A hydraulic brake line is leaking. Which of the following is the correct repair procedure?

Replace the leaking line with double-flared steel tubing

When discussing wheel bearings, all of the following statements are true

Tapered wheel bearings are most commonly used on drive axles.

Technician A says that tapered roller bearings can be adjusted using a torque wrench. Technician B says that tapered roller bearings are adjusted using a dial indicator. Who is right?

Technician A Technician B

Technician A says that when rebuilding a caliper with a stroking seal, the condition of the caliper bore surface is critical. Technician B says that when rebuilding a caliper with a fixed seal, the condition of the piston surface is the most important consideration. Who is right?

Technician A Technician B

A customer complains that their vehicle pulls to the right when the brakes are applied. Technician A says a restricted brake line to the left caliper can cause this problem. Technician B says a malfunctioning proportioning valve is probably the cause. Who is right?

Technician A only

A vehicle's brake pedal is pumped rapidly 20 times and then held down. The master cylinder cover is then removed and when the pedal is released, a geyser is seen coming from the reservoir. Technician A says that this indicates that air is trapped in the system. Technician B says that this means that fluid is being forced out of the cylinder bore through the compensating ports and is normal master cylinder operation. Who is right?

Technician A only

During a brake inspection, an area of the vacuum brake booster below the master cylinder is found to be damp. Technician A says that this is a normal condition. Technician B says that any evidence of fluid indicates a leak and the master cylinder must be replaced. Who is right?

Technician A only

Technician A says that ABS wheel speed sensor gap should be adjusted with a non-magnetic feeler gauge. Technician B says that a paper spacer can be used to adjust ABS wheel speed sensor gap but the paper must be removed before the vehicle is operated. Who is right?

Technician A only

Technician A says the number on the brake drum shown above indicates the maximum diameter, beyond which the drum should not be used. Technician B says the number indicates the maximum diameter the drum can be machined to. Who is right?

Technician A only

Technician A says the rear brake shoes should be properly adjusted before adjusting the parking brake. Technician B says the parking brake lever should be disengaged before adjusting the equalizer. Who is right?

Technician A only

The hydraulic system on a vehicle with integral ABS is to be bled. Technician A says that the front brakes can be bled in a conventional manner. Technician B says that both front and rear brakes can only be bled using the pressure from a fully charged accumulator. Who is right?

Technician A only

Two technicians are discussing the duo-servo type drum brake design. Technician A says the brake lining on the secondary shoe is usually longer and thicker than the brake lining on the primary shoe. Technician B says the primary shoe is installed toward the rear of the vehicle. Who is right?

Technician A only

Two technicians are discussing traction control systems. Technician A says that some traction control strategies do not use the brakes to control wheel spin. Technician B says that a fault in the ABS does not affect traction control. Who is right?

Technician A only

A customer complains that the parking brake will not keep his car stationary. The car has four-wheel disc brakes. Technician A says the caliper levers could be out of adjustment. Technician B says the brake shoes could need adjustment. Who is right?

Technician A only Technician B only

New disc brake pads have just been installed. Technician A says the new pads must undergo a burnishing process during the road test to 'cure' the pads. Technician B says the new pads must be burnished to seat them on the rotor. Who is right?

Technician A only Technician B only

Technician A says that surge bleeding is used in conjunction with manual or pressure bleeding. Technician B says that surge bleeding is used to remove air that is trapped in the brake hydraulic system. Who is right?

Technician A only Technician B only

Two technicians are discussing Electronic Stability Control (ESC) systems. Technician A says the ESC control module uses inputs from the steering wheel rotation sensor and wheel speed sensors to calculate the driver's intended path. Technician B says the ESC control module uses inputs from the lateral acceleration and yaw rate sensors to calculate the vehicle's actual path. Who is right?

Technician A only Technician B only

A few minutes after the engine was turned off on a vehicle with vacuum power assist, the brake pedal is applied and it is hard to push. Technician A says that this is a normal condition. Technician B says that the booster check valve is leaking. Who is right?

Technician B only

A front brake hose is being replaced. On this type of hose, the male end threads directly into the caliper. Technician A says the end of the hose that attaches to the steel brake line should be connected first. Technician B says that a new copper sealing washer should be used when the hose is connected to the caliper. Who is right?

Technician B only

A vehicle's ABS warning light is on and a DTC for the left front wheel speed sensor is found in the computer's memory. When check with an oscilloscope, the waveform for the left wheel speed sensor is erratic and uneven. Technician A says the sensor air gap is excessive. Technician B says the tone ring is probably damaged. Who is right?

Technician B only

In the above illustration, Technician A says that new brake shoes are being adjusted after installation.Technician B says that the procedure shown above is being done so the brake drum can be removed. Who is right?

Technician B only

On a vehicle with single piston floating caliper front disc brakes, the brake pads on the left side of the vehicle are almost completely worn while the right side is almost new. Technician A says that too much rotor runout could be the cause. Technician B says that a binding caliper piston could be the cause. Who is right?

Technician B only

Technician A says as brake fluid ages, it can corrode ABS control valves. Technician B says brake fluid corrodes the copper in the brake lines. Who is right?

Technician B only

Technician A says that DTCs can be accessed from any ABS system using flash diagnostics. Technician B says that ABS system tests can be performed with a bidirectional scan tool. Who is right?

Technician B only

Technician A says that a caliper seal installed in the caliper bore is called a stroking seal. Technician B says that when the brake pedal is released, the piston in the caliper moves back in its bore due to the action of the piston seal. Who is right?

Technician B only

Technician A says that all 3-channel ABS systems use only 3 wheel speed sensors.Technician B says that a 4-channel ABS system means that fluid pressure is independently regulated to each of the wheels during an ABS stop. Who is right?

Technician B only

Technician A says that any imperfection found in a phenolic caliper piston warrants replacement. Technician B says that a phenolic caliper piston should be protected with a block of wood when installing it into the caliper bore with a C-clamp. Who is right?

Technician B only

Technician A says that, when testing a proportioning valve, the pressure at the outlet port to the rear brakes should rise at a faster rate, once transition pressure is reached. Technician B says that vehicles with diagonally-split hydraulic systems must have the proportioning valve tested twice. Who is right?

Technician B only

After applying the brake pedal several times to deplete the fluid reserve in the accumulator of a HydroBoost system, a technician applies the brake pedal with moderate pressure and starts the engine. What should the technician feel at the pedal if the Hydro-Boost system is operating properly?

The pedal should initially move downward before rising up.

A driver complains that the ABS system on his car engages every time he applies the brakes on a cobblestone roadway he uses going back-and-forth to work. This condition means that:

The system is operating normally. The wheels are traveling at different speeds.

All of the following statements about leading-trailing type drum brakes are true EXCEPT:

They are self-energizing.

All of the following could cause a hard brake pedal on a vehicle with power brakes EXCEPT:

a leak in the brake hydraulic system

The purpose of an anti-lock brake system is to maintain tire (wheel) slip at what level?

a level between 10-20%

A customer complains that the brake warning light comes on whenever the brake pedal is depressed while driving. All of the following could cause this to occur EXCEPT:

a short to ground in the warning light circuit

Which component in the Hydro-Boost system provides power assist if there is a loss of hydraulic pressure to the system?

accumulator

A vehicle's brake warning system schematic is shown above. All of the following could cause the brake warning light to stay illuminated EXCEPT:

an open between C237 and C305

All of the following are procedures for removing air from a hydraulic system

bench bleeding

All of the following can cause a vehicle to pull to one side when the brakes are applied

blocked master cylinder compensating port

A technician wants to check the condition of a vehicle's brake fluid. Where should he get the sample to make the most accurate determination?

brake caliper

The above measurement is made when replacing all of the following components EXCEPT:

brake caliper

Brakes that drag or fail to release can be caused by which of the following conditions in the master cylinder?

clogged compensating port

A vehicle exhibits intermittent ABS activation, but when the technician connects a scan tool to the DLC, no DTCs are found. Which of the following could be the cause?

damaged tone wheel teeth loose wheel bearing rust under the wheel speed sensor mount

A customer says that he has just replaced his front disc brake pads himself and now the ABS warning light is on. Which of the following could be the cause?

damaged wheel speed sensor incorrect wheel speed sensor gap stuck ABS solenoid valve

To determine if an intermittent ABS problem is related to an erratic wheel speed sensor signal, which of the following should be used?

digital storage oscilloscope

Excessive slack in the parking brake cables can be eliminated on most vehicles by making an adjustment at the:

equalizer

In the test shown above, vacuum should:

exist on the booster side but not on the engine side

All of the following can be used to apply a non-directional finish to a disc brake rotor

fine file

Which of the following disc brake caliper designs usually allow the brake pads to be removed without removing the caliper?

fixed

Drum brake drag can be caused by all of the following

frozen star wheel

All of the following can cause disc brake squeal

grease on the linings

All of the following are cause for brake rotor refinishing

hard spots

The MOST common cause for premature front brake pad wear in a disc/drum system is:

improperly adjusted rear shoes

Which of the following problems would be caused by using a residual check valve in a disc brake master cylinder?

increased brake pad wear

Which of the following is the MOST cost-efficient method of correcting excessive lateral runout on a disc brake rotor?

indexing

All of the following can cause a problem in the Hydro-Boost system

leaking check valve

The driver of a vehicle with power disc/drum brakes says that the brake pedal moves slowly to the floor while maintaining pedal pressure at a stoplight. What could cause this problem?

leaking primary piston cup in master cylinder

Which of the following is the MOST correct wheel cylinder repair procedure?

loosen the bleeder screw, disassemble, clean and hone, clean and assemble

On a car with disc/drum brakes, the front brakes grab quickly when light pedal pressure is applied. This problem could be caused by a bad:

metering valve

A technician has just overhauled the front brakes on a vehicle with front disc and rear drum brakes. However, when he attaches a pressure bleeder (pressurized to about 25 psi) to the master cylinder, he cannot get any fluid to come out of the disc brake caliper bleeder screws. Which of the following is MOST LIKELY the cause?

metering valve release button not activated

To determine the serviceability of a brake drum, all of the following should be checked E

minimum thickness

Technician A says that an integral ABS system is an add-on system. Technician B says that a non-integral ABS system is a high-pressure system. Who is right?

neither technician A,technician B

Which of the following should be used to measure the thickness of a scored rotor?

outside micrometer with pointed anvil and spindle

A complete front brake service has just been performed on a vehicle with disc brakes: rotors turned, calipers rebuilt, new brake pads, bearings repacked and adjusted. However, when the vehicle is road tested, a pulsation can be felt through the pedal. Which of the following is the MOST LIKELY cause of the pulsation?

over-torqued lug nuts

Which of the following brake symptoms can be caused by wheel bearing problems?

pedal pulsation brake pull grabbing

Brake fluid leaking from a cracked brake line causes the brake light on the dashboard to come on in response to the loss of hydraulic pressure. Which of the following valves in the hydraulic system switched on the light?

pressure differential valve

What is the purpose of the master cylinder residual check valve(s) on vehicles equipped with drum brakes?

prevents air from entering the hydraulic system

While on a road test, a technician notices that the rear wheels lockup and the car skids when attempting to stop quickly from a high speed. The MOST LIKELY cause of this problem is a defective:

proportioning valve

Which of the following would MOST LIKELY happen if the measurements taken from the check shown above varied from the manufacturer's specifications?

pulsating brake pedal

The set-up shown above is used to check:

rotor lateral runout

All of the following disc brake rotor measurements can be performed using a micrometer EXCEPT:

runout

The parking brake pedal on a vehicle with automatic parking brake release remains depressed when the vehicle is placed in drive. All of the following are possible causes EXCEPT:

seized cables

All of the following could cause a pulsation to be felt in the brake pedal EXCEPT:

seized caliper piston

All of the following could cause the parking brake to not hold a vehicle on a grade EXCEPT:

seized wheel cylinder

Which of the following should be used to clean a disc brake rotor after it is machined?

soap and water

When replacing an integral hub/bearing assembly on a front wheel drive vehicle, all of the following must be removed EXCEPT:

steering knuckle

What is the purpose of the bar that is being removed from the brake assembly shown below?

to force the shoes into the drum when the parking brakes are applied