CDL Air Brake - Commercial Driver's License Air Brakes Foundation Brakes and Parts Questions and Answers

Question 1

Which of the following are the three main types of foundation brakes used on vehicles with air brake systems?

Accepted Answer

S-cam, disc, and wedge brakes

Answer

S-cam, hydraulic, and wedge brakes

Answer

Disc, magnetic, and S-cam brakes

Answer

Drum, disc, and electromagnetic brakes

Question 2

During a pre-trip inspection of S-cam brakes, you pull on the slack adjuster and find it has more than one inch of free play. What does this most likely indicate?

Accepted Answer

The brakes are out of adjustment.

Answer

The air compressor is failing.

Answer

The brake drum is cracked.

Answer

The air tanks need to be drained.

Question 3

What is the primary function of the S-cam in a foundation brake system?

Accepted Answer

To force the brake shoes apart and against the brake drum.

Answer

To convert air pressure into mechanical force.

Answer

To store compressed air for the brake system.

Answer

To automatically adjust for brake lining wear.

Question 4

A driver is operating a truck with automatic slack adjusters. What is the correct procedure for ensuring they are working properly?

Accepted Answer

Check that the pushrod travel does not exceed the limit when pulling on it by hand; if it does, it indicates a problem.

Answer

Manually adjust them with a wrench during every pre-trip inspection to ensure they are tight.

Answer

Perform several full, firm brake applications and then check for excessive pushrod travel.

Answer

Loosen the adjustment nut slightly to prevent the brakes from dragging.

Question 5

Which component in a drum brake assembly converts the linear motion of the brake chamber pushrod into rotary motion to apply the brakes?

Accepted Answer

Slack adjuster

Answer

Brake drum

Answer

Return spring

Answer

Anchor pin

Question 6

Compared to traditional S-cam drum brakes, what is a primary advantage of air disc brakes?

Accepted Answer

They are less prone to brake fade because they dissipate heat more efficiently.

Answer

They are less expensive to manufacture and replace.

Answer

They require more frequent manual adjustments to maintain performance.

Answer

They have a longer service life due to thicker friction material.