190105cB truck/tracto air brake system components - part B

Question 1

what are the 5 basic circuits of a dual air brake system? name there colors
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Answer 1

• supply [blue]
• primary [green]
• secondary [red]
• parking/emergency brake circuit [orange]
• trailer control circuit [unknown]
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Question 2

what are the 2 purposes of the parking/emergency brake circuit
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Answer 2

• hold the truck, fully loaded at a 20% grade
• automatically apply actuated spring brakes, known as emergency brake application
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Question 3

witch circuit applies the emergency/parking brakes on air equiped trucks? the primary or secondary service reservoirs
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Answer 3

it’s both the primary and secondary service reservoirs and they do it through a double check valve
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Question 4

difference between spring brake chambers and service brake chambers?
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Answer 4

• spring brake chambers are pressurized air released and spring applied
• service brake chambers are pressurized air applied and spring released
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Question 5

what happens when an operator makes a service brake application?
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Answer 5

• primary service air activates the foundation brakes
• air pressure from the parking/emergej2ncy circuit continue to keep the spring compressed
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Question 6

if the operator manually activates the parking brake circuit or it’s engaged automatically by pressure falling below safe operation limits, what happens in the brake chambers?
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Answer 6

the air pressure acting on the spring brake chamber diaphragm is exhausted and the spring expands, engaging the the brakes
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Question 7

what’s a cage bolt for?

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Answer 7

to MECHANICAL RELEASE the spring brakes

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Question 8

when can you NOT engage your cage bolt

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Answer 8

during normal vehicle operations

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