Truck Air Brake System Components

Question 0

When referring to timing or balance of air to a system which is which?

Answer 0

Balance is from the right to left side.

Timing is from axel to axel.

Question 1

What is the engine rpm number when doing a compression build test?

Answer 1

1250 rpm

Question 2

Name the 5 air circuits.

Answer 2

• supply circuit
• primary service circuit
• secondary service circuit
• parking/emergency circuit
• trailer control circuit.

Question 3

What are the supply circuit components?

Answer 3

Compressor
Governor
Air dryer
Supply and primary and secondary reservoirs.

Question 4

How is compressor air delivery measured in?

Answer 4

Cubic feet per minute. CFM.

Question 5

How many psi will the governor give for the compressor to take a break?

Answer 5

20 to 25

Question 6

What are air dryers filled with?

Answer 6

Descendant beads.

Question 7

How many times more do the reservoirs have to hold more then all the brakes chambers on a truck?

Answer 7

12 times more. It’s law.

Question 8

Why are they called dual air beak systems?

Answer 8

Because trucks have a primary and a secondary system.

Question 9

What does a safety valve do and when does it?

Answer 9

A safety valve protects the system from excessive air pressure. It will blow off at 150 psi.

Question 10

When does the air pressure warning system come on at?

Answer 10

60 psi.

Question 11

Why should synflex not be used directly to the brake pots?

Answer 11

Because it does not do so well when it bends a lot. Use brake hose.

Question 12

What is a dual brake circuit valve?

Answer 12

It is practically two relay valves in one. A treadle valve.

Question 13

In these three positions what are the inlet and exhaust valves doing?
Applied
Hold
Released

Answer 13

Applied: inlet open. Exhaust closed
Hold: inlet and exhaust closed
Released: inlet closed. Exhaust open

Question 14

What is crack pressure?

Answer 14

The amount of air pressure it takes to push the piston down to let air in the valve.

Question 15

What is the purpose if a quick release valve?

Answer 15

To give the air a place to exhaust quicker before the treadle valve.

Question 16

What kind of air comes to the parking brake side of the chamber?

Answer 16

Blended air from both primary tank and secondary tank through the park valve so that if one tank fails it will not lock up the brakes.

Question 17

How are service and park brakes applied and released?

Answer 17

Service brakes are air applied and spring released.

Park brakes are spring applied and air released.

Question 18

With a automatic drain valve, when does it drain water?

Answer 18

When there is a decrease in reservoir pressure.