Heavy truck brakes Study guides, Class notes & Summaries

in the AL factor the L refers to the? length of the slack adjuster Spring brakes on an air-brake vehicle must be able to hold the vehicle, facing uphill or downhill, on what percentage grade? B 20% How much free movement should exist between a slack adjuster and its camshaft? .005 in. max The warning light on a truck with a antilock brake system light when the truck is started. When the truck is moving, the light stays on. which of the following could be the cause? Misad...

When a truck has no air pressure in its tanks, which warning devices are activated when the ignition key is turned on? A buzzer, a dash gauge and a red light What legislation mandates every required standard of a highway truck air brake system? FMVSS 121 If a truck is FMVSS 121 compliant, which of the following air reservoirs must be incorporated into the air brake circuit? Supply, primary and secondary tanks In a truck air brake system which sub circuit is primarily resp...

CDL Air Brake Practice Test|Complete Questions with A+ Graded Answers The 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...

Aumt Brake Final Exam |Complete Questions with Graded A+ Answers Tech A says that parking brakes on drum brake vehicles use separate brake shoes for backup in an emergency. Tech B says that parking brakes on drum brake vehicles mechanically operate the standard drum brake shoes. Who iscorrect? Tech B Which of these drum brake systems uses servo action in both directions? Duo-servo drum brake systems Tech A says that brake shoe linings saturated with brake fluid from a leaky wheel cy...

Final Exam for Brakes Questions and Answers Graded A+ FMVSS Federal Motor Vehicle Safety Standard Antilock Braking Systems To prevent wheel lockup during excessive braking Kinetic Energy The energy in mass in motion Leverage To increase mechanical force and transfer it to the booster Compensating Port The port in the master cylinder that access fluid return to the reservoir

HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE Graded A+ AN ENGINE BRAKE (JACOBS BRAKE) A. IS A SELF-ENERGIZING SERVO TYPE. B. IS NORMALLY USED IN PLACE OF A SPRING BRAKE. C. RESTRICTS THE INTAKE PORT AND CAUSES A BUILD UP OF 30-45 LBS OF PRESSURE. D. OPENS THE EXHAUST VALVES NEAR THE TOP OF THE COMPRESSION STROKE TO RELEASE THE COMPRESSED AIR. (CORRECT AWNSER) IN THE SYSTEM SHOWN BELOW, THE PART AT C IS: A. AN INVERSION VALVE. (POSSIBLE CORRECT AWNSER) B. A SAFETY VALVE. C. A MOD...

CDL Air Brakes |Complete Questions with Graded A+ Answers After every working day Oil and water usually collect in compresed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks? Why drain water from the compressed air tanks? Water can freeze in cold weather and cause brake failure. The air brake system for a straight truck or bus should not leak at a rate of more than __________ psi per minute with the engine off and the brakes released. 2 ...

CDL Air Brakes |Complete Questions with Graded A+ Answers Air loss in a straight truck or bus should not be more than how much PSI with the engine off and the brakes on? 3 PSI in one minute To make an emergency stop with air brakes, using the stab braking method, you should Brake as hard as you can get off brakes when wheels lock get back on brakes when wheels start rolling again All vehicles with air brakes must have what signal? Low air pressure warning signal It is ac...

Michigan CDL Air Brakes Exam Complete Questions with Graded A+ Correct Answers 3 different braking systems that make up Air Brakes Service Brake, Parking Brake, Emergency Brake Air Compressor Pumps air into storage tanks and connected to the engine via gears or a v-belt. Air Compressor Governor Controls when the air compressor will pump air into the air storage tanks. When tank pressure rises to the cut-out level, the governor stops the compressor from pumping. When the tank pressu...

ASE S4 Brakes |Complete Questions with Graded A+ Correct Answers The air system is maintained at what pressure? 100 to 120 pounds per square inch. At what pressure does the low pressure switch activate? Below 60 pounds per square inch. A safety or pop off valve is usually installed in which reservoir? In the one closest to the compressor. Why is the Wet tank referred to as such? It is the one closest to the compressor and has the most water in it. What is an after cooler...