CDL Air Brakes TestInspecting Air Brake SystemsHard
During a pre-trip inspection, a driver observes that the automatic slack adjusters on a vehicle require manual adjustment. What does this indicate?
- AThere is likely a mechanical problem with the slack adjuster or the brake components it operates.
- BThe brake linings are new and have not yet bedded in.
- CThe vehicle is equipped with manual slack adjusters, not automatic.
- DThe automatic slack adjusters are functioning correctly.
Show answer & explanationAnswer & explanation
Correct answer: A. There is likely a mechanical problem with the slack adjuster or the brake components it operates.
Automatic slack adjusters are designed to maintain correct brake adjustment automatically. If they require manual adjustment, it indicates a defect with the slack adjuster itself or another mechanical problem in the brake assembly (e.g., weak return springs, worn cam bushings) that the automatic adjuster cannot compensate for.
Why the other options are wrong
- B. New linings might require initial bedding, but automatic adjusters should handle subsequent adjustments.
- C. This implies a misidentification; the question states they are automatic slack adjusters.
- D. Correctly functioning automatic slack adjusters should not require manual adjustment.
Automatic Slack Adjuster Malfunction
Automatic slack adjusters should not require manual adjustment. If they do, it signals a deeper mechanical issue with the adjuster or the brake components it's connected to.
- Designed to self-adjust.
- Manual adjustment indicates a defect.
- Can be due to worn components like cam bushings or adjuster itself.
Memory trick: Auto-adjuster needs a hand? A deeper problem's in the land!