Page 57 - Draft 2023 2024 CDL Manual w Modernization Info

SECTION 6: COMBINATION VEHICLES

Step 2. Inspect Area and Chock Wheels Step 9. Lock Trailer Brakes • After raising landing gear, secure the crank
• Make sure area around the vehicle is clear. Pull out the "air supply" knob or move the handle safely.
tractor protection valve control from "normal" • When full weight of trailer is resting on tractor:
• Be sure trailer wheels are chocked or spring to "emergency." » Check for enough clearance between rear
brakes are on. of tractor frame and landing gear. (When
• Check that cargo (if any) is secured against Step 10. Back Under Trailer tractor turns sharply, it must not hit land­
movement due to tractor being coupled to • Use lowest reverse gear. ing gear.)
the trailer. » Check that there is enough clearance be­
• Back tractor slowly under trailer to avoid hit­ tween the top of the tractor tires and the
Step 3. Position Tractor ting the kingpin too hard. nose of the trailer.
• Put the tractor directly in front of the trailer. • Stop when the kingpin is locked into the fifth
(Never back under the trailer at an angle be­ wheel. Step 16. Remove Trailer Wheel Chocks
cause you might push the trailer sideways Remove and store wheel chocks in a safe
and break the landing gear.) Step 11. Check Connection for Security place.
• Check position, using outside mirrors, by • Raise trailer landing gear slightly off ground.
looking down both sides of the trailer. 6.4.2 - Uncoupling
• Pull tractor gently forward while the trailer Tractor-Semitrailers
Step 4. Back Slowly brakes are still locked to check that the trailer The following steps will help you to uncouple
is locked onto the tractor.
• Back until fifth wheel just touches the trailer. safely.
• Don't hit the trailer. Step 12. Secure Vehicle Step 1. Position Rig
• Put transmission in neutral.
Step 5. Secure Tractor • Put parking brakes on. • Make sure surface of parking area can sup­
port weight of trailer.
• Put on the parking brake. • Shut off engine and take key with you so • Have tractor lined up with the trailer. (Pull­
• Put transmission in neutral. someone else won't move truck while you ing out at an angle can damage landing gear.)
are under it.
Step 6. Check Trailer Height Step 2. Ease Pressure on Locking Jaws
• The trailer should be low enough that it is Step 13. Inspect Coupling • Shut off trailer air supply to lock trailer
raised slightly by the tractor when the tractor • Use a flashlight, if necessary. brakes.
is backed under it. Raise or lower the trailer
as needed. (If the trailer is too low, the tractor • Make sure there is no space between upper • Ease pressure on fifth wheel locking jaws by
may strike and damage the trailer nose; if the and lower fifth wheel. If there is space, some­ backing up gently. (This will help you release
trailer is too high, it may not couple correctly.) thing is wrong (kingpin may be on top of the the fifth wheel locking lever.)
closed fifth wheel jaws, and trailer would
• Check that the kingpin and fifth wheel are come loose very easily). • Put parking brakes on while tractor is push­
ing against the kingpin. (This will hold rig
aligned.
• Go under trailer and look into the back of the with pressure off the locking jaws.)
Step 7. Connect Air Lines to Trailer fifth wheel. Make sure the fifth wheel jaws Step 3. Chock Trailer Wheels
have closed around the shank of the kingpin.
• Check glad hand seals and connect tractor
Chock the trailer wheels if the trailer doesn't
emergency air line to trailer emergency glad • Check that the locking lever is in the "lock" have spring brakes or if you're not sure. (The air
position.
hand. could leak out of the trailer air tank, releasing its
• Check glad hand seals and connect tractor • Check that the safety latch is in position over emergency brakes. Without chocks, the trailer
service air line to trailer service glad hand. locking lever. (On some fifth wheels the catch could move.)
must be put in place by hand.)
• Make sure air lines are safely supported • If the coupling isn't right, don't drive the
where they won't be crushed or caught while Step 4. Lower the Landing Gear
tractor is backing under the trailer. coupled unit; get it fixed. • If trailer is empty, lower the landing gear
until it makes firm contact with the ground.
Step 14. Connect the Electrical Cord and
Step 8. Supply Air to Trailer Check Air Lines • If trailer is loaded, after the landing gear
• From cab, push in "air supply" knob or • Plug the electrical cord into the trailer and makes firm contact with the ground, tum
move tractor protection valve control from fasten the safety catch. crank in low gear a few extra turns. This will
the "emergency" to the "normal" position to lift some weight off the tractor. (Do not lift
supply air to the trailer brake system. • Check both air lines and electrical line for trailer off the fifth wheel.) This will:
• Wait until the air pressure is normal. signs of damage. » Make it easier to unlatch fifth wheel.
» Make it easier to couple next time.
• Check brake system for crossed air lines. • Make sure air and electrical lines will not hit
» Shut engine off so you can hear the brakes. any moving parts of vehicle. Step 5. Disconnect Air Lines and
» Apply and release trailer brakes and listen Electrical Cable
for sound of trailer brakes being applied Step 15. Raise Front Trailer Supports • Disconnect air lines from trailer. Connect air
(Landing Gear)
and released. You should hear the brakes line glad hands to dummy couplers at back
move when applied and air escape when • Use low gear range (if so equipped) to begin of cab or couple them together.
the brakes are released. raising the landing gear. Once free of weight,
» Check air brake system pressure gauge for switch to the high gear range. • Hang electrical cable with plug down to pre­
signs of major air loss. vent moisture from entering it.
• Raise the landing gear all the way up. (Never
• When you are sure trailer brakes are work­ drive with landing gear only part way up as it • Make sure lines are supported so they won't
ing, start engine. may catch on railroad tracks or other things.) be damaged while driving the tractor.
• Make sure air pressure is up to normal.

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