Table of Contents

7. Doubles and Triples

• 7.1. Pulling Double/Triple Trailers
• 7.2. Coupling and Uncoupling
• 7.3. Inspecting Doubles and Triples
• 7.4. Doubles/Triples Air Brake Check

Use the seven-step inspection procedure described in Section 2 to inspect your combination vehicle. There are more things to inspect on a combination vehicle than on a single vehicle. Many of these items are simply more of what you would find on a single vehicle. (For example, tires, wheels, lights, reflectors, etc.) However, there are also some new things to check. These are discussed below.

7.3.1 - Additional Checks

Do these checks in addition to those already listed in Section 2, Step 5: Do Walkaround Inspection.

Coupling System Areas

• Check fifth wheel (lower).
  • Securely mounted to frame.
  • No missing or damaged parts.
  • Enough grease.
  • No visible space between upper and lower fifth wheel.
  • Locking jaws around the shank, not the head of kingpin.
  • Release arm properly seated and safety latch/lock engaged.
• Check fifth wheel (upper).
  • Glide plate securely mounted to trailer frame.
  • Kingpin not damaged.
• Air and electric lines to trailer.
• Electrical cord firmly plugged in and secured.
• Air lines properly connected to glad hands, no air leaks, properly secured with enough slack for turns.
• All lines free from damage.
• Sliding fifth wheel.
  • Slide not damaged or parts missing.
  • Properly greased.
  • All locking pins present and locked in place.
  • If air powered, no air leaks.
  • Check that fifth wheel is not so far forward that tractor frame will hit landing gear, or cab hit the trailer, during turns.

Landing Gear

• Fully raised, no missing parts, not bent or otherwise damaged.
• Crank handle in place and secured.
• If power operated, no air or hydraulic leaks.

Double and Triple Trailers

• Shut-off valves (at rear of trailers, in service and emergency lines).
  • Rear of front trailers: OPEN.
  • Rear of last trailer: CLOSED.
  • Converter dolly air tank drain valve: CLOSED.
• Be sure air lines are supported and glad hands are properly connected.
• If spare tire is carried on converter gear (dolly), make sure it's secured.
• Be sure pintle-eye of dolly is in place in pintle hook of trailer(s).
• Make sure pintle hook is latched.
• Safety chains should be secured to trailer(s).
• Be sure light cords are firmly in sockets on trailers.

7.3.2 - Additional Things to Check During a Walkaround Inspection

Do these checks in addition to subsection 5.3, Inspecting Air Brake Systems.

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