Air Brakes and Braking Systems Flashcards
7 cards from real 310T practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Air Brakes and Braking Systems flashcards as text
Which type of slack adjuster requires manual repositioning when brake lining clearance exceeds specifications?
Answer: Manual slack adjuster
Manual slack adjusters must be physically repositioned by a technician using a wrench to restore proper pushrod stroke, unlike ASAs which adjust automatically.
What is the purpose of the caging bolt on a spring brake chamber?
Answer: To mechanically compress the power spring so the brakes can be released without air
The caging bolt winds through the chamber head to mechanically compress (cage) the power spring, allowing brake release when no air is available for maintenance or towing.
A truck's air dryer purges more frequently than normal. What is the MOST likely cause?
Answer: Worn compressor rings causing excessive moisture and oil carry-over
Worn compressor piston rings allow oil and moisture past the rings, overloading the dryer desiccant and causing more frequent purge cycles.
What is the FIRST thing a driver should do if the low air pressure warning activates while driving?
Answer: Safely bring the vehicle to a stop before pressure drops further
When the low air warning activates, the driver must safely stop the vehicle immediately, as continued pressure drop will cause automatic spring brake application.
In S-cam foundation brakes, what converts the rotational force of the cam into outward shoe movement?
Answer: Roller followers on the brake shoes
Rollers at the toe of each brake shoe ride the lobes of the S-cam; as the cam rotates, the rollers are pushed apart, forcing the shoes outward against the drum.
Which regulation requires commercial motor vehicles to have their air brake systems inspected and certified annually?
Answer: 49 CFR Part 396
49 CFR Part 396 (Inspection, Repair, and Maintenance) requires annual vehicle inspections that include air brake system checks by a qualified inspector.
What symptom would MOST likely indicate a leaking service brake chamber diaphragm?
Answer: Slow brake application and release with audible air leak at the chamber
A torn service chamber diaphragm allows air to escape rather than build pressure in the chamber, resulting in slow or weak application and an audible leak at the chamber itself.