Unit F: Air Brakes Flashcards
When referring to the primary brake circuit of an air brake ABS system, the ABS modulator valve can be located between the relay valve and the brake chamber.
True or False
True
A brake chamber generating 2000 lb of force on a slack adjuster 6 inches in length will cause _____ lb-in of torque.
12,000 in-lb
As of ____, ABS became mandatory on most new air-braked heavy-duty trucks.
1998
A brake chamber generating 2200 lb of force on a slack adjuster 6 inches in length will cause ____ lb-in of torque.
13,200
The dual-circuit brake valve controls the primary and ____ service circuits.
Secondary
Which ABS component is connected to the ECU?
Speed Sensor
Removing material from the inside of a brake drum by machining will improve the heat dissipation of the brake drum.
True or False
False
The service line glad-hands are often colour coded ____.
Blue
When referring to an air brake ABS system, the ECU monitors the ____ of each wheel.
Rotational speed
The gap between the ABS speed sensor and tone ring should be ____.
As small as possible
The maximum ____ diameter of a brake drum is stamped to the brake drum.
Inside
The maximum belt deflection of an air brake system air compressor is __. (inches or mm)
1/2 to 3/4 inch or 12 to 18 mm
A standard relay valve will have a crack pressure of ____ psi.
2 to 4
The loss of air pressure on the supply line of a pre- 121 trailer will result in ____.
Dynamiting of the trailer brakes
Which of the following would be an output of the ECU? Tone ring Speed sensor Brake modulator valve Brake lights
Brake modulation valve
The quick release valve installed in the supply line of the trailer being towed is to provide ____ of the supply line to the unit being towed.
Quick exhast
____ allow airflow in one direction only.
Single check valves
The function of the quick release valve is to provide a faster brake release.
True or False
True
Cam-operated foundation air brakes are known as ____ brakes.
Non-servo
When referring to an air brake system, the component that converts the linear motion of the brake chamber to a rotary motion is the ____.
Slack adjuster
The term commonly used to describe the coefficient of friction between the vehicles tires and the road surface is ____.
Traction
A properly adjusted cam-operated foundation brake ensures that the ____ are as close as possible to the brake drum without drag.
Brake linnings
When referring to a cam-operated heavy truck air brake system, ____ are usually used to operate the steer axle brakes.
Flat cam shafts
The brake light switch is ____.
Normally open
A large amount of water in the air reservoirs of an air brake system indicates a problem with ____.
The moisture control system
Which of the following would not be a basic component on a pre-121 trailer air brake circuit?
Trailer service and supply lines
Trailer spring brake control valves
Trailer reservoir
Trailer brake chamber and foundation brakes
Trailer spring brake control valve
