Nebraska CDL Combination Vehicles cheat sheet

Combination Vehicles

• Fifth wheel: check jaws are fully closed around the kingpin by pulling the release handle and tugging the trailer with the tractor; the kingpin should be visible in the jaw opening.

• Air lines: connect the emergency (red) line first, then the service (blue) line; after connection, listen for leaks and confirm the trailer air pressure builds to at least 100 psi.

• Landing gear: fully raise the gear before moving; if the tractor is not under the trailer, the gear must support the trailer's nose weight without sinking into soft ground.

• Trailer air brakes: after charging the system, release the parking brake and check that the trailer brakes release; then apply the trailer hand valve (if equipped) and confirm the trailer brakes hold.

• Tractor protection valve: test by closing the trailer air supply valve (red knob) and confirming the trailer brakes apply; the valve should pop out and the trailer brakes should stay applied.

• Off-tracking: in a turn, the rear wheels of the trailer follow a shorter path than the front wheels; the longer the wheelbase, the greater the off-tracking, so swing wide and watch the trailer's rear in mirrors.

• Swing-out: the rear of the trailer swings outward when turning; the longer the trailer, the greater the swing-out, so check mirrors and allow extra clearance on the inside of the turn.

• Coupling checklist: inspect kingpin and fifth wheel, back under the trailer, secure the tractor, connect air lines, raise landing gear, and test the coupling by pulling the tractor forward gently.

• Uncoupling: park on level ground, set the trailer parking brake, lower the landing gear, disconnect the air lines, release the fifth wheel, and pull the tractor forward slowly while watching for the trailer to settle.