Section 5 Flashcards
Why must air tanks be drained?
Water and oil tend to collect in the bottom of the air tank.
What is a supply pressure gauge used for?
Tell you how much pressure is in the air tanks.
All vehicles with air brakes must have a low air pressure warning signal.
True or False?
True
Front wheel brakes are good under all conditions.
True or False?
False
How do you know if your vehicle is equipped with antilock brakes?
Tractors, trucks, and buses will have yellow ABS malfunction lamps on the instrument panel.
Trailers will have yellow ABS malfunction lamps on the left side, either on the front or rear corner.
What is a dual air brake system?
A dual air brake system has two separate air brake systems, which use a single set
of brake controls. Each system has its own air tanks, hoses, lines, etc. One system typically operates the regular brakes on the rear axle or axles. The other
system operates the regular brakes on the front axle (and possibly one rear axle).
What are the slack adjusters?
Help to keep the brakes adjusted
How can you check slack adjusters?
Park on level ground and chock the wheels to prevent the vehicle from moving. Release the parking brakes so you can move the slack adjusters. Use gloves and
pull hard on each slack adjuster that you can reach. If a slack adjuster moves more than about one inch where the push rod attaches to it, it probably needs
adjustment.
How can you test the low pressure warning signal?
Shut the engine off when you have enough air pressure so that the low pressure warning signal is not on. Turn the electrical power on and step on and off the brake
pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 60 psi in the air tank
How can you check that the spring brakes come on automatically?
Continue fanning off the air pressure in the tanks until the parking brake valve closes or pops out engaging the spring brakes
What are the maximum leakage rates?
<2 psi/min for singles
<3 psi/min for combination
Why should you be in the proper gear before starting down a hill?
So you do not wear out brakes.
What factors can cause brakes to fade or fail?
excessive heat, thin linings, overuse, out of adjustment
The use of brakes on a long, steep downgrade is only a supplement to the braking effect of the engine.
True or False?
True
If you are away from your vehicle only a short time, you do not need to use the parking brake.
True or False?
False
