Automotive Brake Systems
A vehicle equipped with a vacuum brake booster has no power assisted stops with the engine off but operate normally with the engine running. Which of the following is the most likely cause
A leaking check valve
All of the following statements about Hydro-boost system accumulators are true except
Accumulators are only pressurized when the pump flow stops
Oil or petroleum based solvents can cause the brake system rubber components to
All of the above
All of the following statements about bench bleeding master cylinders are true except
Bench bleeding is most effective when fluid is allowed to squirt out into the bench
An intake manifold vacuum check valve for vacuum power brakes is being discussed. Technician a says that the valve closes to retain vacuum in the booster. Technician B says that the valve closes to keep atmospheric pressure from reaching the master cylinder side of the booster diaphragm. Who is correct
Both
Brake systems are being discussed. Technician a says the service brakes may be drum or disc. Technician B says ABS may not slow a vehicle faster but it allows better control of the vehicle. Who is correct
Both
Break balance is being discussed. Technician a says this is a serious challenge for small rear wheel drive pick up trucks. Technician B says break balance is the breaking force between the front and rear brakes. Who is correct
Both
Break friction materials are being discussed. Technician a says molding bits of metal into brake lining produces in excellent friction material. Technician B says composite linings can be made from organic fibers or materials. Who is correct
Both
Pushrod adjustment is being discussed. Technician a says a loss of breaking power can result if the pushrod adjustment is too short. Technician B says hello brake pedal can result if the pushrod adjustment is too short. Who is correct correct
Both
Right to know training is being discussed. Technician a says the location of the MSDS should be covered during training. Technician B says the employer must keep records of all training sessions. Who is correct
Both
Spray brake cleaners are being discussed. Technician a says use the container label to determine if the cleaner is hazardous. Technician B says the MSDS should be readily available if the cleaner is in fact considered hazardous. Who is correct
Both
Technician a says OSHA regulates exposure and handling of asbestos. Technician B says the EPA regulates the storage and disposal of asbestos. Who is correct
Both
Technician a says a bearing and race should be replaced together technician B says a bearing should be removed using a brass drift and a hammer. Who is correct
Both
Technician a says a bearing and race should be replaced together. Technician B says a bearing should be removed using a brass drift and a hammer. Who is correct
Both
Technician a says a hydraulic power booster unit is installed in the same place as a vacuum booster. Technician B says the function of the hydraulic power booster is to multiply the force of the drivers foot on the break pedal. Who is correct
Both
Technician a says a low fluid level in the reservoir may indicate worn brake pads. Technician B says a small geyser of brake fluid from only one master cylinder reservoir chamber when the brake pedal is applied may indicate abnormal cup wear. Who is correct
Both
Technician a says a low pedal may be caused by Air in the hydraulic system. Technician B says a low pedal may be caused by improperly adjusted shoes. Who is correct
Both
Technician a says a pushrod in a vacuum power assist unit directly controls the movement of the diaphragm. Technician B says the pushrod operates the air valve and vacuum power assist unit. Who is correct
Both
Technician a says a restricted vacuum feed hose may cause loss of assist after several quick break applications. Technician B says brake fluid and vacuum feed hose indicates a leaking master cylinder rear secondary seal. Who is correct
Both
Technician a says an electrical circuit must have voltage in order for the amperage to perform work. Technician B says a lack of resistance in electrical device (load) Will prevent work being performed to the extent it was designed. Who is correct
Both
Technician a says brake tubing should be double flared or ISO flared. Technician B says an ISO tubing seat must be used with the ISO flare. Who is correct
Both
Technician a says disc brakes are more effective than drum brakes. Technician B says disc brakes require more application pressure than drum brakes. Who is correct
Both
Technician a says dragging brakes may be caused by an improperly adjusted pushrod. Technician B says a leaking air control valve in the vacuum booster could cause the brakes to be slightly applied at all times. Who is correct
Both
Technician a says dragging brakes may be caused by insufficient brake pedal free play. Technician B says free play is defined as the distance the brake pedal moves before the master cylinder primary piston moves. Who is correct
Both
Technician a says improper toe on one rear wheel will create a thrust angle change in the rear axle. Technician B says setback is usually caused by an accident. Who is correct
Both
Technician a says most late model vehicles are equipped with computer-controlled break and stop lamp circuits. Technician B says on some vehicles the turn signals and brake lamp switches are inputs to a module that delivers power to the respective bulbs. Who is correct
Both
Technician a says one piston of a dual master cylinder may supply pressure to one front wheel and one rear wheel. Technician B says a piston may supply pressure only to the brakes on each axle. Who is correct
Both
Technician a says service manual schematic diagrams can make troubleshooting electrical problems easier. Technician B says if several circuits fail at the same time, check for a common ground or power circuit. Who is correct
Both
Technician a says some types of problems in the steering system can affect the Hydro boost system. Technician B says some types of problems in the Hydro boost system can affect the steering system. Who is correct
Both
Technician a says that a stuck closed vacuum check valve in the power break booster may cause a hard pedal problem. Technician B says that a vacuum check valve may be installed in a vacuum booster. Who is correct
Both
Technician a says that power steering fluid pressure can be stored by a spring in an accumulator. Technician B says that brake fluid can be stored under gas pressure in an accumulator. Who is correct
Both
Technician a says the air vacuum valves used on a tandem diaphragm must control vacuum and atmospheric pressure on two diaphragms at the same time. Technician B says when the brakes on a tandem diaphragm system are released, there is a vacuum on both sides of each diaphragm. Who is correct
Both
Technician a says the brake warning light will remain on with the ignition switch in the run position if the parking brake is partially applied. Technician B says a low brake fluid level in the master cylinder may cause the break warning light to come on. Who is correct
Both
Technician a says the finish on a vehicle could be damaged by brake fluid. Technician B says brake fluid irritate the skin in most instances of direct exposure. Who is correct
Both
The results of a metering valve pressure test are being discussed. Technician a says the valve is functioning properly when it closed at 25 psi. Technician B says the valve is functioning properly when it reopened at 275 psi. Who is correct
Both
Which of the following statements are true? A. Celsius temperature for the freezing point of water is 0°. B. The boiling point of water is measured on the Fahrenheit scale as 212°
Both
Vehicle has brakes that are dragging. Technician A says the fluid may be contaminated with a petroleum product. Technician B says the pushrod may be misadjusted. who is correct.
Both A and B
All of the following are types of tubing and hose fittings except
Compression
All master cylinder and booster internal components should be cleaned in
Denatured alcohol
All the following are types of brake fade except
Drum
The metering valve is most necessary during heavy break application.
False
The tire placard is always mounted in the glove compartment
False
The operation of a height sensing proportioning valve can be affected by the installation of
Helper springs and air-assist shocks
On a vacuum boosted system, all of the following can cause poor power-assist unit operation except
High manifold vacuum
Brake line diameter is usually specified as the ______ diameter of the line
Inside
A metering valve is being discussed. Technician a says the valves normally rebuilt. Technician B says the valve is needed for traction control. Who is correct
Neither
Brake cleaning is being discussed. Technician a says using low pressure sprays produces no hazardous waste. Technician B says gasoline works best because it dissolves the dust and can be brushed off. Who is correct
Neither
Brake fluid flushing is being discussed. Technician a says all manufacturers require fluid to be flushed at certain intervals. Technician B says to flush the system with clean water before adding fresh brake fluid. Who is correct
Neither
Tech a says the fluid flows from the master cylinder to the wheel assembly and back to the reservoir on a return type master cylinder. Technician B says that the amount of pressure developed by the master cylinder is dependent on pedal effort, type of brake fluid and booster size/diameter. Who is correct
Neither
Technician a says DOT 3 and DOT 4 brake fluid's have a higher boiling point than DOT 5. Technician B says DOT 4 brake fluid has a higher wet boiling point then DOT 5. Who is correct
Neither
Technician a says air enters the booster chamber from inside the engine compartment. Technician B says the atmospheric pressure is directed to either side of the diaphragm. Who is correct
Neither
Technician a says metric and standard fittings may be interchanged. Technician B says a double flare fitting maybe used to replace an ISO fitting. Who is correct
Neither
Technician a says servo action is accomplished by the opposing forces of the two disc pads per wheel. Technician B says drum brakes require higher application pressure because their shape is similar to that of the drum. Who is correct
Neither
Technician a says the same flaring tool adapters used to make I also can be used to make double flare fittings. Technician B says I am so flares maybe sized in U.S. customary (English) measurements. Who is correct
Neither
Technician a says, with the brakes off, the pressure in the front chamber helps hold the diaphragm in the released position. Technician B says air pressure in the rear chamber counteracts the opposing vacuum to hold the diaphragm in the released position. Who is correct
Neither
DOT 5 Brake fluid's may be mixed with or use to replace
None of the above
Series circuit has
One electrical path
Cups are installed on the master cylinder
Pistons
Most brake pedal installations are an example of what is called a _____-class lever.
Second
Which of the following materials is used for brake lines and brake hoses
Steel and rubber
The quick take up master cylinder is a type of ____ ____ Master cylinder designed for some front wheel drive cars
Step bore
Bearing removal is being discussed. Technician A says a soft material like wood blocks Should be used to support the hub when removing and installing bearings. Technician B says a large blunt steel punch should be used to drive the bearing out. Who is correct
Tech A
Brake tubing is being discussed. Technician a says tubing vibration could cause metal fatigue. Technician B says copper tubing maybe used as break tubing. Who is correct
Tech A
Break warning lights are being discussed. Technician a says a pressure differential in the brake system will switch on the light. Technician B says a typical switch for this light is tripped by vacuum. Who is correct
Tech A
Line and hose fittings are being discussed. Technician a says always use a flare nut (line) Wrench to loosen a line fitting. Technician B says in open end wrench is sufficient for fully tightening the fittings. Who is correct
Tech A
Power assisted brakes are being discussed. Technician a says this system helps the driver in applying braking force. Technician B says the system also aids in reducing wheel lock up. Who is correct
Tech A
Proportioning valves are being discussed. Technician a says proportioning valve's can be found on vehicles with rear disc brakes. Technician B says the proportioning valve is used to increase hydraulic pressure to the rear brakes. Who is correct
Tech A
Technician a says a brake hose usually has a fitting that meets to a flare nut on the line. Technician B says a single flare is typical for a brake line. Who is correct
Tech A
Technician a says a hydraulic brake booster is usually found on vehicles with diesel engines. Technician B says most passenger cars and light trucks use the Hydro boost system. Who is correct
Tech A
Technician a says all modern vehicles have a split braking system. Technician B says that all modern vehicles use a diagonally split system. Who is correct
Tech A
Technician a says installing lowering or lift kits on trucks could affect the operation of the height sensing proportioning valve. Technician B says the combination valve will be affected by adding a lowering or lift kit to the vehicle. Who is correct
Tech A
Technician a says internal rubber parts wear with age. Technician B says internal master cylinder leaks are caused by clogged ports. Who is correct
Tech A
Technician a says that dial indicators are most commonly used to measure the runout of a disc brake rotor. Technician B says that feeler gauges are used to measure disc brake rotor runout. Who is correct
Tech A
Technician a says that friction between the vehicles tires in the road is one factor in stopping the vehicle. Technician B says that her car was locked brakes stops in the shortest time possible. Who is correct
Tech A
Technician a says the Hydro boost power steering fluid reservoir for the pump may be remote from the pump location. Technician B says power steering fluid is same for vehicles. Who is correct
Tech A
Technician a says the hydraulic tubing used in the brake system is always double wall tube. Technician B says break tubing is coded with a tin or lead-based alloy to reduce vibration. Who is correct
Tech A
Technician a says the master cylinder changes mechanical pressure on the brake pedal to hydraulic force. Technician B says the master cylinder operates because liquids can be compressed. Who is correct
Tech A
Technician a says the proportioning valve is an integral part of the master cylinder on some late model vehicles. Technician B says the proportioning valve may be installed in the wheel cylinders. Who is correct
Tech A
Technician a says to diagnose a brake system that does not release, loosen the connection between the master cylinder in the brake booster and recheck. Technician B says if the brakes do not release when the master cylinder is removed from the booster, the booster is defective. Who is correct
Tech A
Technician a says vacuum for the booster is usually supplied by the engine. Technician B says auxiliary controls are used to reduce the vacuum available by diesel engine operation. Who is correct
Tech A
A vehicle has power assist during engine operation, but it has no assist after the engine has been off and during initial engine start up. Technician a says a stuck closed vacuum check valve could be the cause. Technician B says a leaking vacuum check valve could be the cause. Who is correct
Tech B
Electro hydraulic brakes are being discussed. Technician a says these systems use a vacuum booster. Technician B says these systems share information with other electronic systems. Who is correct
Tech B
Pressure bleeding is being discussed. Technician a says to pump the brake pedal several times during the bleed procedure. Technician B says to hold the metering valve open during the bleed procedure. Who is correct
Tech B
Servicing a system with electric/hydraulic brakes is being discussed. Technician a says servicing these systems is no different from servicing conventional systems. Technician B says some EHB systems use brake fluid under high pressure as for a power assist. Who is correct
Tech B
Technician A says changing tire and wheel size does not affect breaking effort or distance. Technician B says that changing wheel offset could affect wheel bearing wear and accelerate bearing failure. Who is correct
Tech B
Technician a says a dual master cylinder uses two matching primary pistons. Technician B says the pistons create separate pressures for 2 wheels each. Who is correct
Tech B
Technician a says a small ripple in only one section of the reservoir as the brakes are being applied is normal. Technician B says a small geyser in the reservoirs as the brakes are being applied is normal. Who is correct
Tech B
Technician a says all pressure differential valves must be manually recentered after bleeding. Technician B says a recentering spring is used on some pressure differential valves. Who is correct
Tech B
Technician a says rusted through brake line rarely occurs. Technician B says break tubing can become twisted and damaged during wheel cylinder replacement. Who is correct
Tech B
Technician a says that dynamic rear proportioning (DRP) is provided by the brake pedal position (BPP) sensor. Technician B says that dynamic rear proportioning (DRP) is provided by the antilock brake (ABS) system. Who is correct
Tech B
Technician a says the hydraulic connection between the vehicle frame in the wheel assembly is soft metal tubing. Technician B says a defect in a flexible brake hose may prevent that break from releasing. Who is correct
Tech B
Technician a says the typical wheel cylinder piston is slightly larger than a caliper piston. Technician B says some of a drum brakes force maybe increased by the rotation of the drum. Who is correct
Tech B
Technician a says when the vacuum diaphragm is in a balanced or "at rest" condition, The booster air valve is open. Technician B says vacuum is always present at the master cylinder side of the diaphragm. Who is correct
Tech B
The normal operation of a dual piston master cylinder is being discussed. Technician a says the secondary piston is moved by the pushrod. Technician B says the primary piston produces the pressure to move the secondary piston. Who is correct
Tech B
Which of the following statements about parking brake function is true
The main purpose is to prevent the vehicle for moving after it is stopped
Brake pedal pressure is increased by all of the following except
The size of the brake rotor
Which of the following conditions is most likely to cause handling problems during breaking on a vehicle with factory-equipped wheels and tires
Tire inflation
During removal of a vacuum booster, the master cylinder should be
Unbolted from the booster and moved a side with the lines still attached if possible
When packing a wheel bearing with grease by hand you should do all of the following except
Wash/dry with compressed air by spinning and check for wear
All of the following may cause the red brake warning light to illuminate except
Worn brake pads
