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Figure  7-16.Trailer  kingpin.
Figure  7-19.Air  line  storage  dummy  couplers.

Equipment Operator Basic - Beginning construction equipment operators manual
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Figure  7-18.—Electrical  connector. .  Check the rear of the tractor frame and the landing gear for enough clearance to make turns. .   Ensure there is enough clearance between the top of the tractor tires and the nose of the trailer. Step 14. Remove trailer wheel chocks o Remove and store wheel chocks in a safe place. The basic steps for uncoupling a tractor from a trailer are as follows: Step 1. Position tractor and trailer Ensure the parking area surface can support the weight of the trailer. Ensure the tractor is lined up with the trailer, if at all possible, because pulling out at an angle can bend and damage the landing gear. Step 2. Ease pressure on locking jaws l l l Shut off trailer air supply or engage the trailer hand valve to lock the trailer brakes. Ease pressure on the locking jaws by backing up gently. (This procedure helps you release the fifth wheel  locking  lever.) Apply the parking brakes while the tractor is backing; this holds the tractor in place with the pressure of the kingpin off the locking jaws. Step 3. Lower the landing gear l  Chock  the  trailer  wheels. If the trailer is empty: lower the landing gear until it makes firm contact with the ground. If the trailer is loaded: after the landing gear makes firm contact with the ground, turn the crank in low gear a few extra turns; this lifts some weight  off  the  tractor  suspension. NOTE: Do not lower the landing gear so low that it lifts the trailer off the fifth wheel because doing this makes it harder to couple and uncouple. Step 4. Disconnect electrical cable Disconnect the electrical cable and hang the cable with the plug down to prevent moisture from entering it. Ensure the electrical cable is supported so it will not be damaged while driving the tractor. Step 5. Unlock fifth wheel Raise the safety catch over the locking pin (if so equipped). Pull the release handle to the “open” position. WARNING Keep legs and feet clear of the rear of the tractor wheels to avoid injury should  the  tractor  move. Step 6. Pull tractor partially clear of trailer Pull tractor forward until the fifth wheel comes out from under the trailer. Stop with the tractor frame underneath the trailer. This  prevents  the  trailer  from  falling  to  the ground if the landing gear should collapse or sink. Step 7. Secure tractor Apply  the  parking  brake. Disengage the trailer hand valve to release trailer brakes. Place the manual transmission in neutral; in park, if an automatic transmission. 7-17







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