Chapter 43/44/45/46 Brakes
If a retracting tool is not avilible, which of the following can be used to retract the pistons in a caliper with non integrated parking brakes
A c-clamp
Vacuum boosters consist of all of the following components EXCEPT
A combination valve
Brake systems not repaired properly can cause
Accidents, Injuries and Death
With the engine running, the check valve allows___ to be evacuated from the booster, but not to return
Air
Tech A states that improperly brake can function reasonably well under normal driving situations. Tech B states that improperly repaired brakes can fail during a panic situation.
Both A and B
Which of the following brake fluids has the highest wet boiling points?
DOT 5
Inspect ____ for cracks, buldging and wear
Flexible brake hoses
Which of the following is NOT a type of lever
Lever of the fourth order
The valve that reduces rear brake pressure when the vehicle is lightly loaded and allows higher pressure when it is heavily loaded is:
Load-sensitive proportioning valve
Tech A says that DOT 5 brake fluid should be used in all vehicles today because it is silicone based and will not absorb water. Tech B says that DOT 4 and DOT 3 are not recommended for use in ABS systems.
Neither A or B
Tech A says that light-duty service are typically applied hydraulically. Tech B says that light-duty parking brakes are typically applied hydraulically.
Tech A
All of the statements are true EXCEPT:
The smaller brake caliper pistons on the front wheels give greater mechanical force and braking power to the front wheels.
A flush using ______ can be performed to remove any remaining and all air
Both B and C
The booster chambers are seperated by a ___ diaphrahm attached to the diaphagm plate
FLexible rubber
Identify a true statement with respect to an air-operated brake:
It is easier to connect and dissconnect the brake lines as only air will leak out
All of the below statements are true except:
A service brakes consist of drum and/or disc brakes and are operated by hand
As a safety measure, part of the hydraulic booster system includes a ___, which assists the maintaining reserve of sytem pressure
Accumulator
BRake pad wear indicators may ne either mechanical or
Electrically actuauted
Dual-Diaphragm boosters apply, hold, and release _____ a single-diaphragm booster
In the same manner as
Which of the following variables is related to pressure and force in a hydraulic system?
Input/Output force and Working pressure
Which of the following can cause brake system dragging
Internal master cylinder leak
To measure free play in the brake pedal, apply very light hand pressure to the brake epdal and measure how far the pedal travels before______
Resistance is fel
All of the following can cause brake system dragging
Stuck caliper pison, misadjusted master cylinder pushrod length and restricted brake line or hose
Tech A states that brake repair is equal with steering and suspension repair on the liability scale. Tech B states that technicians are not liable for improper brake repair.
Tech A
Tech A says that a cracked brake hose that is not leaking does not need to be replaced. Tech B says that a brake hose with a bulge must be replaced
Tech B
Parking brake styles include which of the following
Top hat, Drum style and Tranmission-mounted parking brake
In humid or wet climates, the brake fluid may need to be flushed every
Two years
the kind of brake fade caused by the brake fluid becoming so hot that it boils is
hydraulic fade
When a vacuum-type power booster is used, the driver will be required to increase foot pressure to activate the brakes if there is
insufficient vacuum
when a vacuum-type power booster is used, the driver will be required to increased foot pressure to activate the brakes if there is
insufficient vacuum
Disc brake systems that are equipped with low-drag brake calipers use
quick take-up master cylinders
all of the following statements with respect to replacing brake lines, brake hoses, fittings, and supports are true except
reassemble the removed components using tools only
when the driver releases the brake pedal, the brake shoes are withdrawn at the
return spring
A dial indicator may be used for measuring rotor
runout
____ are a simple mechanical system that use leverage to force a friction block against one or more wheels
scrub brake
This type of flare is sometimes called a bubble flare
International Standards Organization
Which of the following flares is created by first flaring the end of the tube outward in a Y shape?
Inverted double flare
Standard brake fluid is hygroscopic, which means
It readily absorbs water
Disc brake rotos can fail in two way : parallelism and
Lateral runout
As the vehicle is____, the chassis squats on the rear suspension and the lever is moved, applying more force on the load-sensitive proportiong valve
Loaded
___ are designed to maintain a larger brake-pad-to-rotor clearance by retracting the pistons a little bit further than other calipers
Low drag calipers
Always follow the ____ precedures when servicing braking systems
Manufacturer
Different lever designs can be engineered to alter the brake pedal effort required of the driver by using different levels of:
Mechanical advantage
Which of the following is used to hold off the application of the front brakes on vehicles with disc brakes on the front wheels and drum brakes on the rear wheels?
Metering valve
Tech A says that the metering valve controls pressure to the rear brakes. Tech B says that the proportioning valve controls pressure to the front brakes.
Neither A or B
Tech A states that the band brake system working well in the reverse direction. Tech B states that the band would try to unwind in the forward direction.
Neither A or B
If the brake warning lamp always stays on in the run position, you will need to disconnect the four switches___ to see if the warning light goes off
One at a time, checking
All of the following should be researched before performing any brake tasks EXCEPT:
PCM wiring diagram
Which brake is used for holding a vehicle in place when it is stationary
Parking brake
The principle behind hydraulic brakes is ____, which states that pressure applied to a fluid in one part of a closed system will be transmitted without loss to all other areas of the system.
Pascals Law
_____ is the distance the brake pedal travels from its rest position to its applied height
Pedal travel
All of these components are used to modify the pressures within the hydraulic braking system EXCEPT
Pressure differential control units
Diagnosing a drum drum concern will always be as simple as stepping on the brake pedal without moving the vehicle and feeling the level that the brake pedal sinks to
False
During hydraulic braking system bleeding, the pressure differntial valve will never need to be centered
False
When diagnosing the brake warning lamp, always begin by removing the bulb and measuring its resistance with an ohm meter
False
Determining if brake fluid should be flushed can be done using all of the following EXCEPT
Flame test
WHen the driver steps on the brake pedal, is moves the brake pedal pushrod _____, which transmits movement through the power unit to the msater cylinder piston to apply the brakes.
Forward
_______ is the amount of clearance between the brake pedal linkage and the master cylinder piston
Free play
Which of the following are types of brake fade
Heat, Water and Hydraulic
A substancial leak in the ___ will prevent enough pressure from building to exert the nessesary braking force
Hydraulic system
All of the below statements are true except:
In drum brakes, the heat is created outside of the drum and transferred to the inner surface
The vacuum-assisted power booster uses the difference between engine vacuum and atmospheric pressure to ____ the force that acts on the master cylinder pistons
Increase
If we triple the speed of an object, the kinetic energy will:
Increase by nine times
Check the ____ to the power pooster for signs of brake fluid, which would mean brake fluid is leaking past the primary piston in the master cylinder and front seal of the power booster
Inside of the vacuum hose
To perform a thorough inspection of brake pads, you should
Inspect pads to see if wear it even, retaining hardware and anti noise shims, measure the remaing pads for thickness and compare to specifications
Parking brakes use a ___ to maintain tension on the parking brake cables and assembly when applied
Ratcheting mechanism
Residual pressure that is left in the braking system after the pedal has been released would keep the brake pads slightly applied to the brake rotors, causing brake drag, premature wear and
Reduced fuel mileage
Tech A say that a faulty vacuum booster can affect engine operation. Tech B says that steel brake line can be replaced with a copper line, as it is easier to bend into shape
Tech A
Tech A says that a disc brake operates by clamping friction materials to the outside of a disc. Tech B says that a drum brake operates by clamping friction materials to the outside of a drum.
Tech A
Tech A says that a micrometer is used to measure the rotor thickness variation. Tech B says it measures later runout
Tech A
Tech A says that all vehicles must be fitted with a service and parking brake. Tech B says that only trucks must be fitted with a service and parking brake.
Tech A
Tech A says that brake fluid should periodically be checked for excessive moisture content. Tech B says that brake fluid should be replaced every 12,000 miles. Who is correct?
Tech A
Tech A says that the brake pedal uses leverage to multiply foot pressure. Tech B says that when braking hard while moving forward, the vehicle's weight transfers to the rear wheels, increasing their traction
Tech A
Tech A states that TSB's need to be researched before performing a brake repair. Tech B states that TSB's does not need to be researched if the brake has been recently replaced.
Tech A
Tech A pinching off flexible brake hoses with vice grip is recommened for closing rubber brakes lines. Tech B useing a brake pedal holding tool to slightly apply brakes and blck off the compensation ports of master cylinder is recommended to minimize the brake fluid draing when line or hoses are removed
Tech B
Tech A says that a brake pedal that does not return all the way causes the brake warning light on the instrument panel to stay on. Tech B says that a brake pedal that does not return causes the brake lights to stay on.
Tech B
Tech A says that kinetic energy is created during braking to stop the vehicle. Tech B says that kinetic energy is converted to heat energy during braking.
Tech B
Tech A says that quick take-up master cylinders use two additional pistons to move brake fluid faster. Tech B says that banjo fittings are commonly used to connect brake hoses to wheels brake units.
Tech B
Tech A says that the vacuum booster increases the vacuum in the brake system. Tech B says that the vacuum booster uses vacuum and atmospheric pressure to multiply the driver's foot pressure applied to the master cylinder push rod
Tech B
Tech A says that tire pressure does not affect braking. Tech B says that heavy vehicle loads increase stopping distance.
Tech B
Two techs are discussing Newtons first law of motion. Tech A says that a lightweight vehicle requires as much energy to accelerate as a heavier car. Tech B says that a lighter vehicle requires less energy to accelerate than a heavier vehicle
Tech B
The higher the moisture content in brake fluid, the higher the galvanic reaction and the greater the corrosion it causes
True
The pressure bleeding method may include small-diameter hoses that attach to the bleeder screws and recover all of the old brake fluid
True
The term brake assist (BA) describes an enhanced safety system built into some ABS systems that anticipated a panic stop and applies maximum braking force to slow the vehicle as quickly as possible
True
Scratcher and senor are types of disc brake pad ____ indicator
Wear
____ causes the front wheels to have increased traction allowing them to bear more of the stopping load, and causes the rear wheels to have less traction, reducing the amount of load they can bear
Weight transfer
the component of the drum brake system attached to the backing plate is the
Wheel cylinder
all of the following statements are true with respect to brake fluid handling except
brake fluid is considered to be a top-off fluid
which of the following brake shoes when the drum is installed?
brake spoon
the cycle of energy transformation in a typical vehicle is
chemical heat mechanical kinetic
what happens when bleeding is not done?
the brakes will feel spongy and will not be fully functional.
The brake pedal uses leverage:
to multiply the force applied to the master cylinder
vehicles equipped with disc brakes incorporate a mechanically operated drum-style parking brake in the center of the rear disc brake rotors, commonly called a:
top hat parking brake.
The booster receives approximetly ______ of vacuum from the intake manifold
20"
if 100psi of working pressure is applied to a 2 square inch output piston, how much force will be created?
200
An ___ braking system working by restricting the flow of exhaust gases through the engine by closing a butterfly valve located in the exhaust manifold.
Exhaust
With the engine running, the check valve allows ___ to be evacated from the booster, but not to return
Air
The purpose of caliper guide pins is to
Allow the caliper to move in or out as the brake pads wear
Which of the following is another type of brake system used in trucks
Exhaust, Friction and Jake brake
Clean brake fluid will help dissolve any oil in addition to flushing the system
False
Should pressure in the hydraulic system be lost, such as when the engine stalls or the power steering pump drive belt breaks, the hydraulic booster systems accumulator is designed to store sufficient pressure to provide for ______ full-power applications
A few
Brake bleeder screws enable all of the following tasks to be performed EXCEPT
Bleed air or vacuum from the power booster
Tech A say that input force divided by the area of the input gives working pressure. Tech B says that working pressure multiplied by the surface area of the output piston gives the output force.
Both A and B
Tech A says that as moisture levels increase in brake fluid, the boiling point of the brake fluid decreases. Tech B ssays that the result of brake fluid boiling in brake systems is a spongy pedal and a loss of braking effort at the wheels
Both A and B
Tech A says that friction brake can fade due to overheating of the brake lining. Tech B says that friction brakes can fade due to overheating of the brake fluid.
Both A and B
Tech A says that hydraulic pressure is applied in equally in all directions throughout a closed system. Tech B says that air in the hydraulic system will cause the brake pedal to be spongy.
Both A and B
Tech A says that if a technician is determined to have acted maliciously, he or she can be found criminally negligent. Tech B says that technicians have been successfully sued for improperly repaired brakes.
Both A and B
Tech A says that input force divided by the area of the input gives working pressure. Tech B says that working pressure multiplied by the surface area of the output piston gives output force
Both A and B
Tech A says that proportioning valves reduce brake pressure to the rear wheels and are pressure-sensitive or load-sensitive. Tech B says that load-sensitive proportioning valves adjust rear brake pressure according to the weight of the vehciles load
Both A and B
Tech A says that the heavier the vehicle, the more stopping power is needed. TEch B says that the faster a vehicle is moving, the more braking power is needed
Both A and B
Tech A says that water soaked brake shoes can be a cause of brake fade. Tech B says that disc brakes dissipate heat faster than drum brakes.
Both A and B
Tech A states that giving greater control of the braking system to the conputer increases driving safety. Tech B states that a brake prdal emulator tells the computer how firmly the driver intends to brake.
Both A and B
Tech A states that too much brake force can cause the tire to lose traction and skid. Tech B states that ABS systems have helped reduce the number of vehicle accidents each year.
Both A and B
If the parking brake lamp does not turn off when the parking brake is released____
Check the operation of the other warning lamp switch and check the parking brake lamp circuit
When seating the brake pads just installed in the brake calipers, a techcian should place his or her left foot under teh brake pedal so that when applying the pedal with the right foot, the pedal does not push the master cylinder farther into the master cylinder bore which could
Dislodge sludge and cut the lips of the maste cylinder primary seals
Early automobiles that evolves from horse-drawn buggies made use of a _____ braking system
Scrub
which of these is a simple mechanical system that uses leverage to force a friction block against one or more wheels?
Scrub Brake
In vehicles with an electronic brake proportion function, the pressure reduction is handled electronically and can compensate for differences in traction by monitoring wheel
Slip
Air in the lines will cause what type of problem
Spongy brake pedal
The situations that would call fro adjusting brake pedal free travel include all of the following EXCEPT
The brake warning light is coming on only when the brakes are pressed
A wheel's braking ability depends most on:
The load it is carrying
A lever allows the user to lift a large load over a small distance at one end by applying small force over a greater distance from the other end
True
Because the vacuum noramlly comes from the intake manifold, a leaky power booster can affect the operation of the engine by changing the air fuel mixture
True
Brake pedal travel is calculated by measuring the height of the brake pedal before and after depressing and then subtracting the difference between the two readings
True
Braking occurs by means of stationary brake shoes expanding against the inside of the drum, which creates friction and slows the vehicle.
True
Each valve in a combination valve operates individually, as it was designed and is contained in one unit
True
Generally, the best way to test control valves is to connect a pressure gauge set disigned for the high pressures within a brake system to the input and the output f the valve
True
IF the brake pedal is spongy after the brake system hydraulic repairs, you will need to bleed the brakes of any remainging trapped air in the system
True
If the vehicle is safe to drive, it it common practice to test-drive the vehicle to verify the customer concern
True
On vehicles without ABS, the brake light may come on due to uneual pressure in the hydraulic brake system, which causes the pressure differential valve to activate the brake warning light switch.
True
Some foot-mounted parking brake levers can be released by pulling a release handle, which retracts the ratcheting tang and allows the pedal to return to its rest position
True
The best way to verify the customers brake concern is to operate the vehicle if it is safe to do so
True
The brake pedal is usually suspended from a bracket between the dash panel and the firewall
True
which of the following is used on heavy vehicles and is commonly called air brake?
air operated braking system
Medium and heavy duty. vehicles often require increased braking in situations...........
exhaust brake
All of the following variables are related to pressure and force in a hydraulic system, EXCEPT
finish pressure
the component that prevents a direct path for water spary and first to enter the brake drum is
labyrinth seal
One safe way to test whether a braking problem is at the front or rear brakes is to drive at a low speed and
lightly apply the parking brakes
brake fluid testers are used to test the
moisture content of the brake fluid
When performing a DMM-galvanic test on brake fluid, what is a good specification to use to recommend a brake fluid flsuh
more than 0.3 volts