UNCOUPLING A TRAILER

Park the tractor/trailer combination a level surface. Make sure the parking surface will support the weight the trailer , and make sure that the tractor lined straight with the trailer . Pulling out from under a trailer angle may damage the landing gear .

Pull the trailer air supply valve (red octagonal knob) out apply the trailer parking

Back the tractor slightly ease pressure the fifth wheel jaws. Apply the tractor parking brakes while still backing against the king pin the combination will held with pressure f the fifth wheel jaws.

Block the trailer wheels prevent the trailer from moving.

Lower the trailer landing gear until the gear makes firm contact with the

Disconnect the glad hands and the trailer electrical connector . Connect the glad hands the dummy couplers the back the tractor and install the trailer electrical connector into the receptacle provided the back the cab.

Caution

Make sur e the trailer air lines and electrical cor d e operly suspended they will not become tangled damaged while the tractor being W

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Keep legs and feet clear the tractor r ear wheels avoid serious injury should the vehicle move when the fifth wheel unlocked.

Unlock the fifth

Pull the tractor ahead slightly (approximately twelve inches) that the king pin disengages the fifth wheel jaws.

equipped with air use the air control switch exhaust the air from the suspension air

10. Pull the tractor ahead until the fifth wheel out from under the trailer . Stop the tractor with frame under the trailer . This prevents the trailer from falling should the landing gear collapse sink into the ground.

1 Place the transmission neutral and apply the parking https://www.truck-manuals.net/mack/

Inspect the parked trailer make sure the ground supporting the trailer and the landing gear not

13. equipped with air suspension, use the air suspension control switch reinflate the suspension air bags.

Release the parking brakes and drive the tractor forward until the tractor clear the trailer

Caution

equipped with air suspension, NOT operate the vehicle with the suspension air bags deflated. Always r einflate the suspension air bags after coupling uncoupling a trailer .