Question 16 - Air Brakes Test Practice Test for the CDL

Drum brakes have one chamber. Disc brakes have two or more chambers.

Drum brakes use an S-cam. Disc brakes use a C-clamp.

Drum brakes use an S-cam to separate the brake shoes against the drum. Disc brakes use a caliper to squeeze the brake pads against the disc.

Drum brakes use two counter-rotating drums (or one drum is stationary) to apply braking force. Disc brakes separate the brake shoes using a disc.