How should you check that your service brakes are working properly?Park on level ground, wait until normal air pressure is reached, release the parking brake and move forward slowly at about 5 mph. Then apply the brakes firmlyA straight truck or bus air brake system should not leak at the rate of more than _______ psi per minute with the engine off and the brakes released.2During normal driving, spring brakes are usually held back by:Air pressureThe air compressor stops pumping air at what psi?125The driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks fall below______ psi.60Excessive use of the service brakes results in overheating which can lead to:Expansion of the brake drumsThe most common type of foundation brake found on heavy vehicles is the:S-cam drumIf you must make an emergency stop, brake so you:Can keep your vehicle in a straight lineYour truck or bus has a dual air brake systems. If a low air pressure warning comes on for only one system, what should you do?Stop right away and safely park. Continue only after the system is fixedIf your vehicle has an alcohol evaporator, every day during cold weather you should:Check and fill the alcohol levelThe air loss rate for a straight truck or bus with the engine off and the brakes on should not be more than:3 psi in 1 minuetThe driver must be able to see a low air pressure warning which comes on before pressure in the service air tanks falls below _____ psi.60The braking power of the spring brakes:Depends on the service brakes being in adjustmentThe air brake lag distance at 55 mph on dry pavement adds about______ feet.32Total stopping distance for air brakes is longer than that for hydraulic brakes due to_______ distance.Brake lagIt is accepted that too much heat caused by using your brakes too often can also cause:Brake to fade or failRepeatedly partially increasing and pressing the brake pedal may result in:A loss of brake air pressureThe brake system that applies and releases the brakes when the the driver uses the brake pedal is the_______ brake system.ServiceA slack adjuster's free play needs to be adjusted if it is more than about how many inches when you pull hard on it?1 inchAn air brake system is fully charged at what psi?125The brake pedal in an air brake system:Controls the air pressure applied to the brakesThe S-cam:Forces the brake shoes against the inside of the brake drumUnder normal conditions, in order to engage the parking brakes the driver should:Apply brakes by pulling the parking brake control knob outAll air brake equipped vehicles have:A supply pressure gaugeWith air brake vehicles, the parking brakes should be used:Whenever you leave the vehicle unattendedIf the air compressor should develop a leak, what keeps the air in the tanks?The one-way check valveWhich of these is NOT a proper time to apply the parking brakes?If the brakes are very hot (e.g. Just after coming down a steep grade)With air brake vehicles, the parking brakes should be used:Any time when vehicle is parkedWhy should you drain water from compressed air tanks?Water can freeze in cold weather and cause brake failureIf the spring brakes are on, when should you push the brake pedal?NeverTo check the free play of manual slack adjusters of S-cam brakes, you should park on:Level-ground and chockExcessive heat caused by using your brakes too often can also cause:Brake to fade or failIf you must make an emergency stop, you should brake so you:Can steer and keep your vehicle in a straight lineThe use of brakes on a long and steep downgrade under normal conditions is only a supplement to:The braking effect of the engineThe most important thing to do when a low air pressure warning comes on is:Stop and safely park as soon as possibleThe parking or emergency brake on a heavy vehicle can only be held in a position by something that cannot leak away, like:Spring pressureAir braking takes more time than hydraulic braking because air brakes:Take more time to flow through the lines than hydraulic fluidWhen brakes are applied, the brake shoes will press against the:Brake drum or discThe safety valve discharges automatically at the pressure of:150 psiStab braking:Apply your brakes all the way. Release brakes when wheels lock up. As soon as the wheels start rolling, apply the brakes fully again.If air pressure is not built up within the correct amount of time, then:Air pressure may drop to a low point while driving, requiring an emergency stopThe safety valve reduces pressure at _____ psi.150What can legally hold a parking or emergency brake in position for a truck, truck tractor, or bus?Spring pressureThe supply pressure gauge shows how much pressure:Is in the air tanksThe braking power of the spring brakes:Depends on the brakes being in adjustmentIt is not safe to drive a vehicle that has brake drums with cracks that are longer than ______ of the width of the friction area.1/2Your brakes are fading when:You have to push harder on the brake pedal to control your speed on a downgrade.If your vehicle has an alcohol evaporator, it is there to:Reduce the risk of icing in air brake valves in cold weatherThe air compressor governor controls:When air is pumped into the air tanks.Modern air brakes combine three different systems. They are the service, the parking, and the ___ brakes.EmergencyIf you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage tanks?At the end of each day of drivingThe proper use of the brakes when going down a long steep grade after selecting a proper gear is to brake until your speed is about ___ mph below the posted speed for your safety and release your brake.5 mphIn ideal conditions a truck or bus with air brakes going at 55 mph would require the stopping distance of how many feet?More than 300 feetWhen is it OK to leave your truck unattended without applying the parking brake or chocking the wheels?NeverThe stop light switch:Turns on the brake lights when you put on the air brakesThe ______ shows how much pressure is in the air tanks.Supply pressure gaugeTo test air service brakes you should:Brake firmly while slowly moving forward.If you are driving down a steep downgrade and have reached your safe speed of 40 mph, you would apply the service brake until your speed dropped to_____.35 mphIf your truck has a dual air brake system and one of the systems is low on pressure:Either the front or rear brakes will not be fully functionalWhat happens when your brake drums get very hot?They expandWhat is a "Wig Wag"A mechanical arm that signals low air pressure
