58. What are the slack adjusters?
Detailed Explanation
A slack adjuster is part of the mechanical linkage between the brake chamber pushrod and the S-cam brake camshaft. It converts pushrod movement into rotation of the camshaft and includes a mechanism used to maintain proper brake adjustment. Too much movement at the pushrod connection can indicate excessive brake slack and reduced braking effectiveness.
Official reference: New York DMV CDL-10, Section 5.3: Inspecting Air Brake SystemsCorrect Answer: It is an adjusting nut on the backside of the brake drum used for adjusting the brakes.
Why This Matters on the CDL Test
For an inspection question, remember both identification and condition. On an S-cam system, inspect reachable slack adjusters with the vehicle secured, look for excessive movement, and have an out-of-adjustment automatic adjuster properly repaired.
How to Remember It
Pushrod moves, slack adjuster turns, S-cam rotates, brake shoes contact the drum.
Answer Review
The correct choice identifies the brake-adjustment mechanism located at the brake assembly. More precisely, the slack adjuster is the lever and adjuster connected to the brake chamber pushrod and S-cam shaft, not merely open space between parts of the vehicle.
Why the other answers are weaker
- It is the space between the back wheels.That describes vehicle spacing, not a component of the foundation brake linkage.
- It is an adjusting nut under the cab to adjust the springs.Slack adjusters are located at the brake assemblies and act on the brake camshaft; they do not adjust cab springs.
Test-Day Checklist
- Read the question once for the topic, then read it again for the exact CDL action being tested in Air Brakes.
- Eliminate answers that sound convenient but skip an inspection, warning sign, or safety step.
- Say the correct rule out loud before moving on so you can recognize it when the exam changes the wording.
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To inspect slack adjusters on S-cam brakes, you need to:
110. To check the brake slack on S-cam brakes, you should park on:
26. A slack adjuster's free play needs to be adjusted if it is more than about _______ how many inches when you pull hard on it?
59. How can you check the slack adjuster?
7. To check the brake slack on S-cam brakes, you should park on:
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