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• Check for enough clearance between rear of tractor frame and Landing gear. (When tractor turns
sharply, it must not hit landing gear.)
• Check that there is enough clearance between the top of the tractor tires and the nose of the
trailer.
Uncoupling Tractor-Semitrailers
The following steps will help you uncouple safely.
Step 1 Position Rig
• Make sure surface of parking area can support weight of trailer.
• Have tractor lined up with the trailer. (Pulling out at an angle can damage landing gear.)
Step 2: Ease Pressure on Locking Jaws
• Shut off trailer air supply to lock trailer brakes. Ease pressure on fifth wheel locking jaws by backing
up gently (this will help you release the fifth wheel locking lever).
• Put parking brakes on while tractor is pushing against the kingpin.
• This will hold rig with pressure off the locking jaws.
Step 3: Lower The Landing Gear
• If trailer is empty-lower the landing gear until it makes firm contact with the ground, turn crank in
low gear a few extra turns; this will lift some weight off the tractor. (Do not lift trailer off the fifth
wheel.) This will
• - Make it easier to unlatch the fifth wheel;
• - Make it easier to couple next time.
Step 4: Disconnect Air Lines and Electrical Cable
• Disconnect airlines from trailer. Connect airline glad hands to dummy couplers at back of cab, or
couple them together.
• Hang electrical cable with plug down to prevent moisture from
•
• Entering it.
• Make sure lines are supported so they won't be damaged while driving the tractor.
Step 5: Unlock Fifth Wheel
• Raise release handle lock.
• Pull the release handle to the "open" position.
• Keep legs and feet clear of the rear tractor wheels to avoid serious injury in case the vehicle moves.
Step 6: Pull Tractor Partially Clear of Trailer
• Pull tractor forward until fifth wheel comes out from under trailer.
• Stop with tractor frame under trailer (Prevents trailer from falling to ground if landing gear should
collapse or sink.)
Step 7: Secure Tractor
• Apply parking brake.
• Place transmission in neutral.
Step 8: Inspect Trailer Supports
• Make sure ground is supporting trailer.
• Make sure landing gear is not damaged.
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