Z Endorsement Test - Quiz 02 (30) Flashcards
(30 cards)
You should ascertain whether a trailer uses a spring brake or service brake priority system by…?
Asking your employer or a qualified person
The trailer supply valve is usually operated from the dashboard by a control with a knob of which color?
Red
Which of these can cause the air pressure to drop and so activate the spring brakes?
Any of them
a. Closing the trailer supply valve
b. A ruptured supply line
c. A disconnected supply line
Air brake systems on a trailer have which of these components?
Both of these:
a. Air tanks
b. Automatic spring brakes
What is a ‘gladhand’?
A coupling device
Which of these statements applies to spring brakes?
They are less powerful than service brakes
The tractor protection valve on towing vehicles is designed to do what?
Prevent air loss
Trailer hand valves can be used for…?
Normal braking
Trailer brake subsystems must apply the spring brakes automatically when the trailer supply line pressure drops below…?
414 kPa (60 psi)
In the majority of air brake systems, the parking and emergency brakes are applied by doing what to the control?
Pulling it out
A DD3 Safety Actuator has how many air line connections?
Three
Service line couplings are usually color coded which color?
Blue
The spring brake controls are normally what color?
Yellow
Trailer service brakes can be operated by…?
Either of these:
b. The brake pedal
c. A hand valve
When the tractor protection valve is opened, it allows air to…?
Flow to the trailer service line
Which of these trailers can be towed without waiting for the service brake air tanks to fill?
A trailer with spring brake priority
If a spring brake priority trailer loses air to the service brakes, the trailer can only be braked by…?
Closing the trailer supply valve
Trailer brake subsystems supply air…?
Either service brakes first or spring brakes first; depending on manufacturer
When attaching a trailer, the supply line is usually color-coded what color?
Red
You have finished your delivery and unhitched from your trailer. What should you do with the trailer supply valve?
Pull it out
Which of these is not the type of foundation brake system?
“V” brakes
On which of these vehicles are you most likely to find a DD3 Safety Actuator?
A motorcoach
The trailer supply valve will close automatically when air pressure drops below…?
138 - 311 kPa (20 and 45 psi)
S” cam brakes use which sort of system?
Drum brakes