Coupling A Trailer - Mack Granite GU Series Operator's Handbook Manual

COUPLING A TRAILER

1. Position the tractor directly in front of the trailer.
2. Back the trailer slowly until the fifth wheel just contacts the trailer plate.
3. Place the transmission in neutral and apply the parking brakes.
4. Connect the trailer glad hands and electrical connector.
CAUTION
Make sure the trailer air lines and the trailer electrical cord are properly supported
so they will not be pinched or caught while the tractor is being backed under the
trailer.
5. Check that the fifth wheel height matches the height of the underside of
the trailer. If the trailer is too high, use the landing gear to lower the trailer
until fifth wheel and trailer height match. If the vehicle is equipped with an air
suspension and the trailer is too low, use the air suspension control switch
to exhaust air from the suspension air bags until fifth wheel and trailer height
match.
CAUTION
Failure to match fifth wheel height with trailer height will result in the trailer being
improperly connected.
6. Back under the trailer slowly until the trailer king pin engages. Back slowly
to avoid hitting the king pin too hard, and stop as soon as the king pin is
locked into the fifth wheel.
7. If equipped with an air suspension, use the air suspension control switch
to reinflate the suspension air bags.
8. Raise the trailer landing gear slightly off the ground.
9. With the trailer parking brakes applied, pull the tractor ahead slightly to
ensure that the trailer is locked onto the tractor.
10. Push the trailer air supply valve (red octagonal knob) in to supply the trailer
system with air pressure. With the air system at normal operating pressure,
check the trailer air brake system for excessive leakage and proper operation.
OPERATION 181