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Pennsylvania CDL Combination Vehicles: test 3

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Pennsylvania CDL Combination Vehicles 3

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Question 1 of 5
  1. 1. You are unsure whether the parked trailer has spring brakes. What should you do before uncoupling?
  2. 2. When uncoupling a loaded trailer, how far should you lower the landing gear after firm ground contact?
  3. 3. How should the disconnected trailer electrical cable be stored?
  4. 4. While operating the fifth-wheel release, where should your legs and feet be?
  5. 5. You have pulled the fifth-wheel clear but kept the tractor frame under the trailer. What should you verify before pulling away fully?
Review all 5 questions with answers

  1. You are unsure whether the parked trailer has spring brakes. What should you do before uncoupling?

    Correct answer: Chock its wheels

    Stored air can leak away; use chocks when spring-brake protection is uncertain.

    Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), section 6.4.2 Uncoupling Tractor-Semitrailers — Step 3 Chock Trailer Wheels, printed 6-11 (physical PDF page 117) ↗

  2. When uncoupling a loaded trailer, how far should you lower the landing gear after firm ground contact?

    Correct answer: A few extra low-gear turns, without lifting off the fifth-wheel

    Support some weight to ease release without creating an unsafe gap or over-lifting.

    Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), section 6.4.2 Uncoupling Tractor-Semitrailers — Step 4 Lower the Landing Gear, printed 6-11 (physical PDF page 117) ↗

  3. How should the disconnected trailer electrical cable be stored?

    Correct answer: Supported, plug downward to keep moisture out

    Protect the plug from moisture and the cable from moving parts or road damage.

    Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), section 6.4.2 Uncoupling Tractor-Semitrailers — Step 5 Disconnect Air Lines and Electrical Cable, printed 6-11 (physical PDF page 117) ↗

  4. While operating the fifth-wheel release, where should your legs and feet be?

    Correct answer: Clear of the tractor’s rear wheels

    Unexpected vehicle movement can cause severe injury near the wheels.

    Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), section 6.4.2 Uncoupling Tractor-Semitrailers — Step 6 Unlock Fifth Wheel, printed 6-11 (physical PDF page 117) ↗

  5. You have pulled the fifth-wheel clear but kept the tractor frame under the trailer. What should you verify before pulling away fully?

    Correct answer: The landing gear is sound and the ground supports the trailer

    After pulling partly clear, set the tractor parking brake and select neutral. Check that the ground supports the trailer and the landing gear is undamaged before releasing the brake and pulling fully clear.

    Source: Pennsylvania Commercial Driver's License Manual PUB 223 (6-26), section 6.4.2 Uncoupling Tractor-Semitrailers — Steps 8–9 Secure Tractor / Inspect Trailer Supports; Step 10, printed 6-11 (physical PDF page 117) ↗

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Question reference: pa-cdl-combo-041

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Pennsylvania CDL Combination Vehicles: test 3

5 questions from this subject. 45 questions on tractor-trailer control, coupling, air connections and inspections.

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