Practice Test Geeks(310t) Truck and Coach Technician Certification Practice Test
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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

  1. What is the purpose of the ratio valve (also called a front axle limiting valve) found on some trucks?

    Answer: To reduce front brake application pressure to prevent front wheel lockup on slippery surfaces

    A ratio valve reduces air pressure delivered to the front brakes (typically by 50% in the 'slippery' position) to help prevent front wheel lock-up on low-traction surfaces.

  2. During a pre-trip inspection, a driver should test the spring brakes by:

    Answer: Applying the parking brake and attempting to drive away to verify hold

    FMCSA pre-trip procedure includes applying the parking brake and attempting to move the vehicle in low gear to confirm the spring brakes hold the vehicle stationary.

  3. What is a common cause of brake chamber pushrod stroke being TOO SHORT (under-travel)?

    Answer: Slack adjuster adjusted too tightly (over-adjusted)

    Over-adjustment of the slack adjuster brings the lining too close to the drum, shortening stroke but also risking brake drag and heat buildup.

  4. On an air over hydraulic brake system, what converts the air signal into hydraulic pressure?

    Answer: Air-hydraulic intensifier (booster)

    An air-hydraulic intensifier uses incoming air pressure to actuate a hydraulic piston, generating proportional hydraulic pressure to operate wheel cylinders or calipers.

  5. Which condition would cause a vehicle equipped with ABS to have the ABS warning lamp illuminate and STAY ON after the system self-test?

    Answer: A wheel speed sensor failure or wiring fault detected by the ECU

    The ABS ECU continuously monitors wheel speed sensors; a fault such as a missing or erratic signal causes the warning lamp to remain on and may disable ABS on that circuit.

  6. What is the maximum allowable brake lining thickness before replacement is required per FMCSA brake regulations?

    Answer: 1/4 inch on steering axle, 1/8 inch elsewhere

    FMCSA (49 CFR 393.47) specifies minimum lining thickness of 1/4 inch on steering axles and 1/8 inch on all other axles before the vehicle is placed out of service.

  7. A technician is checking the air brake system and finds oil in the wet tank. What is the MOST likely source?

    Answer: Worn or defective air compressor rings or valve plate

    Worn compressor piston rings or a faulty valve plate allows crankcase oil to pass into the discharge air, depositing oil in the wet tank and throughout the system.