TX CDL Air Brakes 3

Question 1

If your truck or bus has dual parking control valves it means that you can use pressure from a separate tank to:

Answer 1

Release the spring brakes to move a short distance.

Question 2

If the air compressor should develop a leak, what keeps the air in the tanks?

Answer 2

The one-way check valve

Question 3

Brake drums must not have cracks longer than ______ the width of the friction area.

Answer 3

1/2

Question 4

After the initial drop, the maximum acceptable leakage rates per minute are:

Answer 4

3 psi for single vehicles and 4 psi for combination vehicles.

Question 5

How would you check your truck’s slack adjusters?

Answer 5

Use gloves and pull hard on each slack adjuster you can reach.
- If one moves more than about an inch where it’s attached to the rod, it probably needs adjustment.

Question 6

If the low air pressure warning signal light is not working,

Answer 6

it may lead to sudden emergency braking in a single-circuit air system.

Question 7

Under ideal conditions, the average driver of a truck or bus equipped with air brakes and traveling at 55 mph would require what stopping distance?

Answer 7

About 450 feet
- While traveling at 55 mph

Question 8

To check the free play of manual slack adjusters on S-cam brakes you should:

Answer 8

Park on level ground, chock the wheels, and release the parking brakes.

Question 9

Your truck or bust has a dual air brake system. If a low pressure warning comes on for only one system, what should you do?

Answer 9

Stop. Safely park and continue only after the system is fixed.

Question 10

Tractor and straight truck spring brakes will come fully on when the air pressure drops to a range of:

Answer 10

20 to 45 psi.

Question 11

The modulating control valve allows you to control the

Answer 11

spring brakes.