🛞Arizona Air Brakes — Question 4 of 10

The most common type of foundation brake found on heavy vehicles is the:

Answer: B

S-cam drum.

S-cam drums are the most common brake design used on foundation brakes for commercial vehicles. There will be one drum per wheel and operated by using an air-activated push rod to rotate an S-shaped cam to move the shoes into contact with the drums.

Source: Arizona CDL Manual

All choices

  • AWedge drum.
  • BS-cam drum.
  • CDisc.
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Arizona CDL Air Brakes Test Info

Questions on Exam

25

Passing Score

80%

Time Limit

Typically 30 minutes; varies by testing location

Age Requirements

Intrastate: 18+ · Interstate: 21+

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