What type of foundation brake is most common on heavy trucks in North America?

• A.Cable-operated band brakes
• B.S-cam drum brakes
• C.Hydraulic calipers with no air assist
• D.Magnetic eddy-current brakes only

Why

S-cam drum brakes are the long-standing standard because they are durable and work well with air chambers and slack adjusters. Air disc brakes are also in use, but the CDL test focuses heavily on the S-cam design drivers will inspect most often.

Manual topic: Air Brakes - Air Brake System Components · From the Air Brakes practice bank (AB-019).

Practice this subject as a full test

More Dual Air Brake System & Components questions

• What is the main purpose of a dual air brake system on a modern truck?
• In a dual air brake system, what does the primary system typically control?
• In a dual air brake system, what does the secondary system typically control?
• How can a driver monitor a dual air brake system while driving?
• If one circuit of a dual air brake system fails completely, what should the driver expect?