Heavy truck brakes Study guides, Class notes & Summaries

In what year was FMVSS-121 introduced? A. 1997, B. 1998, C. 1975, or D. 1957? 1975 When a truck has no air pressure in its tanks, which warning devices are activated when the ignition key is turned on? A. A buzzer, B. Red light, C. A dash gauge, or D. All of the above. all of the above what legislation mandates every required standard of a highway truck air brake system A. osha B. fmvss 105 C. fmvss 121 D. nhtsa C. FMVSS 121 if a truck is FMVSS 121 compliant, which of the...

he parking or emergency brake on a heavy vehicle can only be held in position by something that cannot leak away, like: a. Fluid pressure b. Spring pressure c. Air pressure d. Any of the above b. Spring pressure A straight truck or bus air brake system should not leak at a rate of more than __ psi per minute with the engine off and the brake released. a. 1 b. 2 c. 3 d. 4 c. 3 Your vehicle has dual air brake system. If low air pressure warning comes on for the secondar...

Where should grease be applied on an S-cam brake system components? cam roller pocket race What is the primary function of a relay valve? remote controlled service brake valve Which of the following factors can affect the timing of service brakes? relay valve crack pressures hose and tubing diameters and length replacing a 45-degree fitting with a 90-degree fitting What is the potential energy of an air brake system? compressed air What are S-cam type foundation...

AL Factor The size or surface area of a brake chamber multiplied by the length of the slack adjuster in inches Anti-fade An opposite condition of heat fade where the coefficient of friction increases as the brakes get hotter. Automatic Slack Adjusters (ASAs) Automatically adjust brake stroke to maintain the correct shoe-to-drum clearance. Brake Block Brake friction material that is 0.75 inch (19mm) thick. Brake Fade The inability of the brakes to maintain its eff...

In hydraulic disc brakes, the pads are forced against the rotors by: the pistons As the pressure of fluid received by the wheel cylinder of a drum brake system increases, which of the following happens? The wheel cylinder cups and pistons are forced apart Which of the following safety devices delays application of front disc brakes in a disc/drum system until pressure is built up in the hydraulic system? a metering valve In a typical air-over-hydraulic brake system, -depr...

heat form of energy in an internal combustion engine motion heat energy produced by engine combustion is converted to in stopping a vehicle, the energy of motion turns the vehicle's wheels, the wheels wont go anywhere unless theres ______ between the tires and the road surface traction what is a car engine heat conversion machine, taking the energy of heat from exploding mixture of fuel and air in the combustion chamber and converting it to motion through the engine cra...

Which of the following is the best practice when instructed to block the wheels on a tractor/trailer combination? Place a pair of wedged wheel chocks on one tractor drive axle and one trailer axle wheel. What is the required amount of slack adjuster free travel on a properly adjusted, manual S-cam brake? 3/8 to 5/8 inch Which of the following foundation brake components are lubricated with chassis grease, either for component life or as part of a lube job? S-cam bushings ...

The vehicle expections report the VIR should be submitted? Weekly Which of the following cannot a drum on an air braked vehicle to overheat? Too-high governor cut out pressure All the brakes drag on a truck with hydraulic brakes which of the following could be the cause? No brake pedal free travel Which of the following could cause a pulsating brake pedal on a truck with hydraulic brakes? And out-of-round brake drum Air pressure gauge charge an air pressure signal...

Which of the following air brake system components functions as a lever? the slack adjuster Which of the following components sets the system cut-in and cut-out pressures? the governor What is the function of a system safety pop-off valve? It relieves pressure from the supply tank in the event of governor cut-out failure. The function of the foot valve or dual-circuit application valve is to: meter air to the service brake circuit The potential energy of an air br...