Disc brakes use replaceable friction material called __________.
Pads
Drum brakes use replaceable friction material called ________.
Shoes
Technician A says that a power-assisted brake reduces stopping distances compared with a non-power-assisted brake system. Technician B says that the power-assisted brake system reduces the force that the driver must exert on the brake pedal. Which technic
Technician B only
A locked wheel ___________________ to the road surface than a rolling wheel.
Has less traction
Technician A says that all vehicles equipped with ABS will experience a pulsating brake pedal even during normal braking. Technician B says that some ABS units only control the rear wheel brakes. Which technician is correct?
Technician B only
The FMVSS 135 standards determine ____________.
The Performance of the Braking system
An owner of a vehicle equipped with ABS brakes complained that whenever he tried to stop on icy or slippery roads, the brake pedal would pulse up and down rapidly. Technician A says that this is normal for many ABS units. Technician B says that the ABS un
Technician A only
Electric adjustable pedals operate___.
Both the accelerator and the brake pedal
What is NOT specified by the FMVSS 135?
Brake Noise Levels
What is the purpose of any brake repair?
To restore like-new performance
True or False: Kinetic energy of a vehicle doubles when the speed doubles.
True
Technician A says that the front brakes do most of the braking because the front brakes are larger. Technician B says that due to weight transfer, most of the braking force needs to be supplied by the front brakes. Which technician is correct?
Technician B only
The brake pedal assembly uses a mechanical lever to __________________
Increase the driver's force on the brake pedal applied to the master cylinder.`
The friction between two surfaces is NOT affected by ______________.
Speed difference between the two surfaces.`
Technician A says that the thicker or heavier the disc brake rotor, the more heat can be absorbed. Technician B says that the faster the vehicle is traveling when the brakes are applied, the greater the amount of heat created in the brake system. Which te
Both Technicians A and B`
What type is not a type of Brake Fade?
Rotor Fade
Brake fade caused by water can occur __________________
When driving through water puddles or during a severe rainstorm
What can the driver do to reduce the possibility of brake fade caused by heat?
Select a lower transmission gear
Maximum deceleration rates for a typical passenger car or light truck is __________.
16 to 32 ft/sec2
Disc brake pads can reach temperatures as high as _____________.
1,300�F (700�C)
Two technicians are discussing master cylinders. Technician A says that it is normal to see fluid movement in the reservoir when the brake pedal is depressed. Technician B says a defective master cylinder can cause the brake pedal to slowly sink to the fl
Both Technicians A and B
The primary brake circuit fails due to a leak in the lines, leaving the rear section of a dual split master cylinder. Technician A says that the driver will notice a lower than normal brake pedal and some reduced braking power. Technician B says that the
Technician A only
Two technicians are discussing a problem where the brake pedal travels too far before the vehicle starts to slow. Technician A says that the brakes may be out of adjustment. Technician B says that one circuit from the master cylinder may be leaking or def
Both Technicians A and B
Air in the lines will cause what type of problem?
Low spongy brake pedal
The master cylinder is able to move about how much brake fluid during each brake application?
One teaspoon
Brake fluid pressure is measured in what unit?
PSI
How much brake fluid is in a typical master cylinder reservoir?
Enough to allow all brakes to become completely worn
What part in the master cylinder helps keep air from contacting the brake fluid yet allows the fluid level to drop as the disc brakes wear?
Rubber diaphragm or floating disc
The brakes on a vehicle work okay for a while, then the vehicle slows because the brakes self-applied. Technician A says that an overfilled master cylinder could be the cause. Technician B says that a blocked vent port (compensating port) could be the cau
Both Technicians A and B
Technician A says a pull to the right during braking could be caused by a defective metering valve. Technician B says a pull to the left could be caused by a defective proportioning valve. Which technician is correct?
Neither Technician A nor B
The rear brakes lock up during a regular brake application. Technician A says the metering valve could be the cause. Technician B says that stuck front disc brake calipers could be the cause. Which technician is correct?
Technician B only
The rear wheels lock up during hard braking. Technician A says that a defective metering valve could be the cause. Technician B says that a defective proportioning valve could be the cause. Which technician is correct?
Technician B only
A combination valve could include__________________.
Proportioning, metering, and pressure-differential valves
A residual check valve is used to ______________.
Maintain a slight pressure on the hydraulic system
Technician A says that the red brake warning light can be turned on if a difference in pressure is detected by the pressure-differential switch. Technician B says that the red brake warning light can be turned on if the brake fluid level sensor detected l
Both Technicians A and B
Which type of vehicles most often do not use metering valves?
Front-wheel drive
Technician A says that some proportioning valves are one part and used to control both rear brakes. Technician B says that some proportioning valves are two parts, one for each rear wheel brake. Which technician is correct?
Both Technicians A and B
The button on the _______________ valve should be held when pressure bleeding the brakes.
Metering
A typical brake light is electrically _________________.
Normally open
The type of brake fluid most often recommended by vehicle manufacturers is _______.
DOT3
Which of the following is not a characteristic of conventional brake fluid?
Lasts the life of the vehicle unless there is a leak Technician A says that DOT 5 brake fluid can be added to DOT 3 brake fluid. Technician B says that it is wise to purchase brake fluid that is in metal rather than plastic containers. Which technician is
As brake fluid ages, what happens?
The boiling temperature decreases.
Technician A says that glycol-based brake fluid causes the seals to swell slightly. Technician B says the DOT 5 (silicone-based) brake fluid causes rubber seals to swell slightly. Which technician is correct?
Technician A only
The two types of flares used on brake lines are _______________.
Double flare and ISO
Two technicians are discussing why the brake lines are coiled near the master cylinder on many vehicles. Technician A says that these coils help prevent moisture from flowing from the master cylinder to the calipers. Technician B says that they help preve
Technician B only
Flexible brake hose should NOT be inspected for :
Worn outer ribs
Why should brake calipers be supported by a wire during brake service and not allowed to hang by the flexible brake hose?
To help prevent damage to the brake hose
Used brake fluid should be _____________.
Disposed of properly according to state and local laws
The button on the ___________ valve should be held when pressure bleeding the brakes.
Metering
The brake bleeding procedure usually specified for a rear-wheel vehicle with a dual split master cylinder is _________________.
RR, LR, RF, LF
Two technicians are discussing bench bleeding a master cylinder. Technician A says that the front (nose end) of the master cylinder should be bled first. Technician B says that the rear (brake pedal end) should be bled first. Which technician is correct?
Technician B only
Two technicians are discussing how to loosen bleeder valves. Technician A says that a shock is usually necessary to break the taper at the base of the valve. Technician B says to apply steady, loosening torque to the bleeder valve using a 6-point wrench.
Technician A only
Technician A says that the brake pedal should be depressed with as much force as possible during the normal bleeding procedure. Technician B says that the brake pedal should be pumped rapidly during this manual bleeding procedure to force the air down tow
Neither Technician A nor B
Vacuum is applied where during vacuum bleeding?
At each wheel brake bleeder valve
The bleeder is opened at a caliper and no brake fluid flows out. Technician A says that this is normal and that brake fluid should not flow or drip out of an open bleeder valve. Technician B says that the vent port in the master cylinder may be blocked. W
Technician B only
The usual maximum pressure that should be used when pressure bleeding a brake system is ______.
30 PSI
How does a bleeder valve seal?
Tapered end
Air in the brake hydraulic system can cause all except ___________.
Hard brake pedal
Which type of automotive bearing can withstand radial and thrust loads, yet must be adjusted for proper clearance?
Tapered roller bearing
Most sealed bearings used on the front wheels of front-wheel-drive vehicles are which type?
Double-row ball bearing
On a bearing that has been shock loaded, the race (cup) of the bearing can be dented. This type of bearing failure is called ___________________.
Brinelling
The bearing grease most often specified is rated NLGI __________________.
#2
A non-drive-wheel bearing adjustment procedure includes a final spindle nut tightening torque of ___________.
Finger tight
After a non-drive-wheel bearing has been properly adjusted, the wheel should have how much end play?
0.001 to 0.005 in.
The differential cover must be removed before removing the rear axle on which type of axle?
C-lock
What part(s) should be replaced when servicing a wheel bearing on a non-drive wheel?
Both the grease seal and the cotter key
Technician A says that a defective wheel or axle bearing often makes a growling or rumbling noise. Technician B says that a defective wheel or axle bearing often makes a noise similar to a tire with an aggressive mud or snow design. Which technician is co
Both Technicians A and B
Two technicians are discussing differentials. Technician A says all differentials are vented. Technician B says that a clogged vent can cause the rear axle seal to leak. Which technician is correct?
Both Technicians A and B
Two technicians are discussing drum brake shoes. Technician A says that forward and rearward facing shoes are the same and can be installed in either position on any drum brake system. Technician B says that the darker color lining should always be placed
Neither Technician A nor B
Two technicians are discussing brake lining edge codes. Technician A says that the code can identify the manufacturer. Technician B says that all friction material from the same manufacturer will have the same edge codes. Which technician is correct?
Technician A only
Technician A says that starwheel adjusters use different threads (left- and right-handed) for the left and right sides of the vehicle. Technician B says that a pawl controls the teeth of the starwheel adjuster. Which technician is correct?
Both Technicians A and B
Technician A says that some drum brakes can fail to slow the vehicle if driven through deep water. Technician B says that when drum brakes get hot, the brake pedal will drop because the drum expands away from the shoes. Which technician is correct?
Both Technicians A and B
Technician A says that the anchor pin (shoe anchor) is used to hold one end of the primary and secondary shoe return springs. Technician B says that the shoe anchor prevents the brake shoes from rotating with the drum when the brakes are applied. Which te
Both Technicians A and B
Drum brake shoes ____________________.
Can have riveted linnings, bonded linnings, and one shoe that is longer than the other on the same wheel brake.
Which lining does most of the braking on a dual-servo brake?
Rear (rearward facing)
Which lining does most of the braking on a leading-trailing brake?
Leading (forward facing)
Two technicians are discussing drum brake self-adjusters. Technician A says that some brakes self-adjust when the brakes are released when the vehicle is driven in reverse. Technician B says that some brakes self-adjust when the brakes are applied rather
Both Technicians A and B
A typical drum brake backing plate has how many shoe support pads (also called ledges)?
6
Technician A says that the tinnerman nuts are used to hold the brake drum on and should be reinstalled when the drum is replaced. Technician B says that a drum should be removed inside a sealed vacuum enclosure or washed with water or solvent to prevent p
Technician B only
The backing plate should be replaced if the shoe contact areas (pads or ledges) are worn more than __________.
1/16 in. (2 mm)
Technician A says that silicone brake grease can be used to lubricate the shoe contact ledges. Technician B says that synthetic brake grease, lithium brake grease, or antiseize compound can be used as a brake lubricant. Which technician is correct?
Both Technicians A and B
Most brake experts and vehicle manufacturers recommend replacing brake lining when the lining thickness is ____________________.
0.060 in. (1.5 mm)
Technician A says that starwheel adjusters use different threads (left- and right-handed) for the left and right sides of the vehicle. Technician B says that the threads and end caps of the adjusters should be lubricated with brake grease before being ins
Both Technicians A and B
Technician A says that many vehicle manufacturers recommend that wheel cylinders not be honed because of the special surface finish inside the bore. Technician B says that some experts recommend that the wheel cylinders be replaced every time the brake li
Both Technicians A and B
Most manufacturers recommend that brake parts should be cleaned with ____________.
Denatured alcohol
Old brake shoes are often returned to the manufacturer when new friction material is installed. These old shoes are usually called the ______________.
Core
After assembling a drum brake, it is discovered that the brake drum will not fit over the new brake shoes. Technician A says that the parking brake cable may not have been fully released. Technician B says to check to see if both shoes are contacting the
Both Technicians A and B
Technician A says to use masking tape temporarily over the lining material to help prevent getting grease on the lining. Technician B says that grease on the brake lining can cause the brakes to grab. Which technician is correct?
Both Technicians A and B
What part causes the disc brake caliper piston to retract when the brakes are released?
The square-cut O-ring
Two technicians are discussing the reason that the brake fluid level in the master cylinder drops. Technician A says that it may be normal due to the wear of the disc brake pads. Technician B says that a low brake fluid level may indicate a hydraulic leak
Both Technicians A and B
Two technicians are discussing a floating-type disc brake caliper. Technician A says that if the caliper slides are corroded, one pad may wear more than the other pad on the same wheel brake. Technician B says that if a caliper slide is corroded, reduced
Both Technicians A and B
Technician A says that disc brakes are self-adjusting and the brake pedal height should not become lower as the disc brake pads wear. Technician B says that as the disc brake pads wear, the level of brake fluid in the master cylinder reservoir drops. Whic
Both Technicians A and B
Which type of disc brake caliper may leak brake fluid more often?
Fixed
A quick take-up master cylinder is required when what type of caliper design is used on a vehicle?
Low-drag
Technician A says that all vehicles equipped with rear disc brakes use a parking brake that is integrated in the caliper. Technician B says that all vehicles equipped with rear disc brakes use a small drum brake inside the rear rotor for a parking brake.
Neither Technician A nor B
The brake pad edge code letters "FF" mean ___________________________.
Coefficient of friction rating
Semimetallic brake pads are made by a process called _______________.
Sintering
Technician A says that riveted disc brake pads are often quieter than bonded disc brake pads. Technician B says integrally molded disc brake pads are molded into holes in the steel backing of the pads. Which technician is correct?
Both Technicians A and B
Uneven disc brake pad wear is being discussed. Technician A says the caliper piston may be stuck. Technician B says the caliper may be stuck on the slides and unable to "float." Which technician is correct?
Both Technicians A and B
A "chirping" noise is heard while the vehicle is moving forward, but stops when the brakes are applied. Technician A says that the noise is likely caused by the disc brake pad wear sensors. Technician B says the noise is likely a wheel bearing because the
Technician A only
Technician A says that disc brake pads should be replaced when worn to the minimum allowable thickness. Technician B says the pads should be removed and inspected whenever there is a brake performance complaint. Which technician is correct?
Both Technicians A and B
A typical disc brake caliper overhaul (OH) kit usually includes what parts?
Square-cut O-ring seal and dust boot
Technician A says that a lack of lubrication on the back of the disc brake pads can cause brake noise. Technician B says that pads that are not correctly crimped to the caliper housing can cause brake noise. Which technician is correct?
Both Technicians A and B
Two technicians are discussing ways of removing a caliper piston. Technician A says to use compressed air. Technician B says to use large pliers. Which technician is correct?
Technician A only
Which is not a recommended type of grease to use on brake parts?
Wheel bearing (chassis) grease
Technician A says that a loaded caliper includes an overhauled caliper assembly, but no brake pads or hardware. Technician B says that a loaded caliper includes the pads and all needed hardware. Which technician is correct?
Technician B only
A vehicle is hoisted during routine service and the service technician discovers that the left front wheel does not turn when force is applied. Technician A says that the hoist (lift) pads could be against the left front tire. Technician B says that that
Both Technicians A and B
Technician A says that a steel piston should be cleaned with sandpaper to remove rust. Technician B says that the brake assembly fluid or clean brake fluid should be used to lubricate the caliper pistons before installing in the caliper. Which technician
Technician B only
Technician A says that the parking brake cable should be adjusted at each wheel. Technician B says that the parking brake cable adjustment is usually done after adjusting the rear brakes. Which technician is correct?
Technician B only
Technician A says that the parking brake hand lever can turn on the red brake warning lamp. Technician B says that a foot-operated parking brake can turn on the red brake warning lamp. Which technician is correct?
Both Technicians A and B
Technician A says that if the parking brake cable is adjusted too tight, the rear brakes may drag and overheat. Technician B says that the parking brake is adjusted properly if the cable is tight when in the released position. Which technician is correct?
Technician A only
On most drum brake systems, the parking brake lever and strut transfer the pulling force of the parking brake cable against the _____________________.
Primary shoe
On most vehicles, the antrattle spring (strut spring) should be installed on the parking brake strut toward the _____ of the vehicle.
Front
In a typical integral rear disc brake caliper, the parking brake cable moves the ___________.
Actuator screw
The rear brakes should be inspected, and adjusted if necessary, if the parking brake requires more than _______.
10 clicks
A rear drum brake is being inspected. The primary shoe is not contacting the anchor pin at the top. Technician A says that this is normal. Technician B says that the parking brake cable may be adjusted too tight or is stuck. Which technician is correct?
Technician B only
Technician A says that a hose clamp can be used to compress the retainer fingers of a parking brake cable in order to remove it from the backing plate. Technician B says a box-end wrench can be used instead of a hose clamp. Which technician is correct?
Both Technicians A and B
Technician A says that an electric parking brake (EPB) uses an electric motor to pull on the parking brake cable. Technician B says that some electric parking brake systems use a computer-controlled motor attached to the caliper. Which technician is corre
Both Technicians A and B
Technician A says that aluminum brake drums use cast iron friction surfaces. Technician B says that up to 0.030 in. (0.8 mm) should be left after machining a drum to allow for wear. Which technician is correct?
Both Technicians A and B
Technician A says that hard spots in a brake drum should be removed using a carbide-tip machining tool. Technician B says that the drum should be replaced if hard spots are discovered. Which technician is correct?
Technician B only
Technician A says that brake drums on the same axle should be close to the same inside diameter for best brake balance. Technician B says that a brake drum may be cracked if it rings like a bell when tapped with a light steel hammer. Which technician is c
Technician A only
A hubless brake drum cannot be machined because it cannot be held in a lathe.
False
The major reason for brake pedal pulsation during braking is due to excessive rotor thickness variation.
False
Rotor finish is measured in ________________.
Microinches
The lower the Ra of a rotor, the _______ the surface.
Smoother
A disc brake rotor is being installed on a lathe for machining. During the setup a scratch test is performed. The scratch extended all the way around the rotor. Technician A says that the rotor should be loosened, rotated 180�, and retightened. Technician
Technician B only
Typical maximum rotor runout specifications are ______________________.
0.003 to 0.005 in. (0.08 to 0.13 mm)
Typical maximum rotor thickness variation (parallelism) specifications are _____________.
...
0.0003 to 0.0005 in. (0.008 to 0.013 mm)
...
Two technicians are discussing vacuum brake boosters. Technician A says that a low, soft brake pedal is an indication of a defective booster. Technician B says that there should be at least two power-assisted brake applications after the engine stops runn
Technician B only
Technician A says that to check the operation of a vacuum brake booster, the brake pedal should be depressed until the assist is depleted and then start the engine. Technician B says that the brake pedal should drop when the engine starts, if the booster
Both Technicians A and B
Brake pedal feedback to the driver is provided by the ________________.
Reaction system
The proper operation of a vacuum brake booster requires that the engine be capable of supplying at least ________________.
15 in. Hg vacuum
The purpose of the charcoal filter in the vacuum hose between the engine and the vacuum brake booster is to __________________.
Trap gasoline vapors to keep them from entering the booster
A defective vacuum brake booster will cause a ___________________.
Hard brake pedal
An accumulator such as that used on hydraulic brake boosters ________________.
Provides a reserve in the event of a failure
The first step in diagnosing a Hydro-Boost problem is ____________________.
A thorough visual inspection
A brake pedal feels spongy when depressed. Technician A says that a defective hydraulic brake booster could be the cause. Technician B says that a defective vacuum brake booster could be the cause. Which technician is correct?
Neither Technician A nor B
If the engine stops running, the Hydro-Boost will not be able to provide any power assist for the brakes.
False
Technician A says that the ABS system may not result in shorter stopping distance compared to brakes without ABS. Technician B says that a pulsating brake pedal during normal braking is a characteristic feature of most ABS-equipped vehicles. Which technic
Both Technicians A and B
The maximum traction between a tire and the road occurs when the tire is _______________.
Slipping 10 to 20 percent
Technician A says that ABS-equipped vehicles can stop quickly and without skidding on all road surfaces even if covered with ice. Technician B says that steering is possible during an ABS stop. Which technician is correct?
Technician B only
A customer wanted the ABS checked because of tire chirp noise during hard braking. Technician A says that the speed sensors may be defective. Technician B says that tire chirp is normal during an ABS stop on dry pavement. Which technician is correct?
Technician B only
Two technicians are discussing ABS wheel speed sensors. Technician A says that some ABS systems use a sensor located in the rear-axle pinion gear area. Technician B says that all ABS systems use a wheel speed sensor at each wheel. Which technician is corr
Technician A only
Technician A says that most ABS units are nonintegral. Technician B says that the ABS is disabled (does not function) below about 5 mph (8 km/h). Which technician is correct?
Both Technicians A and B
Which type of antilock braking system (ABS) requires the use of four wheel speed sensors?
Four channel
Technician A says that ABS brakes are designed to allow the front wheel to be steered during heavy braking. Technician B says that the ABS dash warning lamp is amber. Which technician is correct?
Both Technicians A and B
The faster a wheel rotates, the higher the frequency produced by a wheel speed sensor.
True
Technician A says that some wheel speed sensors are enclosed in a wheel bearing assembly. Technician B says that some wheel speed sensors are exposed to possible damage from road debris. Which technician is correct?
Both Technicians A and B
The red brake warning lamp is on and the amber ABS lamp is off. Technician A says that a fault is possible in the base brake system. Technician B says that the red brake warning lamp can be turned on by a low brake fluid level in the master cylinder. Whic
Both Technicians A and B
Two technicians are discussing magnetic-type wheel speed sensors. Technician A says that wheel speed sensors are magnetic. Technician B says that the toothed sensor ring is magnetic. Which technician is correct?
Technician A only
Technician A says that using the space-saving small spare tire may trigger an ABS amber warning lamp. Technician B says the use of the small spare tire may trigger the red brake warning lamp. Which technician is correct?
Technician A only
Technician A says that, with some antilock braking systems, the diagnostic trouble code may be lost if the ignition is turned off before retrieving the code. Technician B says that some antilock braking systems require that a terminal be grounded to cause
Both Technicians A and B
Technician A says that a scan tool may be required to retrieve data and diagnostic trouble codes from some antilock braking systems. Technician B says that a jumper wire can be used to retrieve diagnostic trouble codes on some antilock braking systems. Wh
Both Technicians A and B
Technician A says that a breakout box is sometimes required to diagnose an antilock braking system. Technician B says that a breakout box requires the use of a digital multimeter. Which technician is correct?
Both Technicians A and B
Technician A says that a noise or vibration may be sensed by the driver when the ABS performs a self-test. Technician B says that the ABS fuse may have to be removed to erase some ABS diagnostic codes if a scan tool is not used. Which technician is correc
Both Technicians A and B
The ABS computer uses what signal characteristic from a wheel speed sensor?
Frequency
Most wheel speed sensors should measure how much resistance?
800 to 1,400 ohms
Technician A says that the ABS electrohydraulic unit can be bled using bleeder screws and the manual method. Technician B says that a scan tool is often required to bleed the ABS electrohydraulic unit. Which technician is correct?
Both Technicians A and B
The electronic stability control (ESC) system requires that the vehicle be equipped with what type of brake system?
Four-channel ABS
Which Federal Motor Safety Standard requires electronic stability control to be on all vehicles by 2011?
126
What is the name of the standard test that is performed to verify ESC operation?
Sine with dwell
What other name is used to describe an electronic stability control (ESC) system?
Vehicle Stability Assist (VSA), Electronic Stability Program (ESP), Vehicle Dynamic Control (VDC)
Which sensor is used by the ESC controller to determine the driver's intended direction?
Steering wheel (hand wheel) position sensor
A diagnostic trouble code (DTC) has been set for a fault with a lateral acceleration sensor or circuit. What test could be performed to check if the sensor is working?
Key on; engine off, hold sensor sideways to see if a scan tool reads 1.0 G
A lateral acceleration sensor is usually located where in the vehicle?
Under the front seat
If a vehicle tends to continue straight ahead while cornering, this condition is called _____.
Understeer
Traction control uses the antilock braking system and other devices to limit __________ of the drive wheels during acceleration.
Positive slip
A traction control system can often control all except ___________.
Engage four-wheel drive
If the brake pedal linkage is not adjusted correctly, brake fluid may not be able to expand back into the reservoir through the ________________ port of the master cylinder when the brakes get hot.
Vent port (forward hole)
A vacuum is described as any pressure that is higher than atmospheric pressure.
False
Two technicians are discussing vacuum suspended brake boosters. Technician A says that when the engine is running and the driver's foot is off the brake pedal, a vacuum is present on both sides of the booster diaphragm. Technician B says that when the bra
Both
When blowing through the vacuum supply hose, if air passes through the check valve into the booster:
Replace the check valve
To provide the driver with a sense of "feel" during braking, vacuum boosters use a:
Reaction disk
A hydraulically operated booster unit stores fluid under pressure by means of:
An accumulator
The proper operation of a vacuum brake booster requires that the engine be capable of supplying at least:
15 in. Hg vacuum
Technician A says power brakes were developed because of increased vehicle weight and increased speed capabilities. Technician B says disc brakes systems all operate with power assist. Which technician is correct?
Tech A only
Two technicians are discussing vacuum brake boosters. Technician A says that a low, soft brake pedal is an indication of a defective booster. Technician B says that there should be at least two power-assisted brake applications after the engine stops runn
Tech A only
Technician A says that to check the operation of a vacuum brake booster, the brake pedal should be depressed until the assist is depleted and then start the engine. Technician B says that the brake pedal should drop when the engine starts, if the booster
Both
When performing a hydro-boost brake booster function test the brake pedal should be depressed several times to discharge the accumulator. When the engine is started, with your foot on the brake pedal, the pedal should:
sink slightly toward the floor, then push back against your foot.
A defective vacuum brake booster will cause a:
Hard brake pedal
The purpose of the charcoal filter in the vacuum hose between the engine and the vacuum brake booster is to:
trap gasoline vapors to keep them from entering the booster
What precaution should be taken before servicing an ABS that uses a high pressure accumulator?
Discharge the accumulator
Modern antilock brake systems typically hold tire slip on dry pavement to between:
5 and 20 percent
Technician A says an antilock brake system will always produce the shortest possible stops. Technician B says when braking on loose gravel or dirt, a system that can lock the wheels can produce shorter stops than an antilock system. Which technician is co
Technician B only
The ABS control module uses the ________ signal from a wheel speed sensor.
Frequency
Which of the following is NOT a function of an antilock brake system (ABS)?
Allows drivers to drive more closely to the vehicle in front
What is the function of the ABS solenoids?
They open and close hydraulic passageways
Technician A says that most ABS units are the integral type. Technician B says that the ABS is disabled (does not function) below about 5 mph (8 km/h). Which technician is correct?
Tech B only
A technician is trying to identify which type of antilock system is installed on a vehicle. A wheel speed sensor is attached to the transmission. Which type of system could this be?
Two-channel ABS
A digital wheel speed sensor produces a(an) ________ type of signal.
Square wave
Technician A says that ABS may not result in shorter stopping distances compared to brakes without ABS. Technician B says that a pulsating brake pedal during severe braking is a characteristic of most ABS-equipped vehicles. Which technician is correct?
Both
The three phases of ABS operation are pressure:
Hold, release, increase
A customer wanted the ABS checked because of tire chirp noise during hard braking. Technician A says that the speed sensors may be defective. Technician B says that tire chirp is normal during an ABS stop on dry pavement. Which technician is correct?
Tech B only
Two technicians are discussing ABS wheel speed sensors. Technician A says that some ABS use a sensor located in the rear-axle pinion gear area. Technician B says that all ABS use a wheel speed sensor at each wheel. Which technician is correct?
Tech A only
Which of the following components is common to all vehicles equipped with ABS?
Hydraulic modulator unit
What causes the ABS control module to switch from a "stand-by" mode to an active mode?
Brake pedal switch
Technician A says that ABS-equipped vehicles can stop quickly and without skidding on all road surfaces even if covered with ice. Technician B says that steering is possible during an ABS stop. Which technician is correct?
Tech B only
Technician A says even though the driver is turning the steering wheel, the vehicle will continue in a straight line if the front wheels are locked. Technician B says the ABS system operates at a higher pressure than the driver does with his/her foot. Who
Tech A only
Technician A states a magnetic-inductive WSS is an active speed sensor. Technician B states a magnetic-inductive WSS produces DC voltage. Which technician is correct?
Niether