80 COMMON AIR BRAKE QUESTIONS AND ANSWERS

Oil and water usually collect in compressed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks? - Answer- After every working day To check the slack adjusters on S-Cam brakes, you should - Answer- Park on level ground, chock the wheels, and release the parking brakes The safety valve is set to automatically reduce pressure at ___ Psi - Answer- 150 If your truck has a properly functioning dual air brake system and maximum-size air tanks, the air pressure should build from 85to 100 psi within ___ seconds. - Answer- 45 During normal driving, spring brake are usually held back by - Answer- Air pressure The driver must be able to see a warning before the pressure in the service air tanks falls below ___ Psi. - Answer- 60 Excessive use of the service brake results in overheating, which can lead to - Answer- Expansion of the brake drums when you are going down a long or steep grade after selecting the proper gear, the proper method of braking is to brake until your speed is about __ miles per hour below your safe speed and then release your brakes. - Answer- 5 The air brake lag distance at 55 MPH on dry pavement adds about ___ feet. - Answer- 32 how can you check the slack adjusters? - Answer- Park on level ground, turn off the parking brakes, and pull hard on each slack adjuster. It shouldn't move more than one inch. The total stopping distance for air brake is longer than that for hydraulic brakes because of - Answer- brake lag Repeatedly pressing and releasing (fanning) the brake pedal may result in - Answer- A loss of brake Air Pressure The parking or emergency brake on a heavy vehicle can only be held n position by something that cannot leak away, like - Answer- Spring pressure Air braking takes more time than hydraulic braking because air - Answer- Takes more than time to flow through the lines than hydraulic fluid. when you apply the bra