In this ongoing series, we have went into great detail about how a professional truck driver should safely couple their trailer. But just as important as coupling is, you’ve got to know how to uncouple it, as well.
We are going to give you a clearly defined 12-step process that will guide you completely through the process of uncoupling a trailer from a tractor. Let’s begin!
Position and Secure
Your first step should be to make sure the parking surface you are on is level and that it can adequately support the weight of the trailer. Dirt, sand and gravel and other uneven surfaces could cause uncoupling problems. If you must, always use trailer supports or boards to prevent the trailer from sinking.
Once you have aligned the tractor with the trailer on an even surface, get out if you must to make absolutely sure they are perfectly aligned. Pulling out an angle could damage the trailer’s landing gear.
Next you want to secure the trailer and ease the pressure on your tractor’s locking jaws. Pull out the trailer air supply button and ensure the trailer brakes are locked.
Next, ease pressure on the fifth wheel locking jaws by giving your vehicle a gentle back up. The pressure of the lock jaws against the kingpin will release.
While the tractor is pushing against the kingpin, slowly put the tractor parking brakes on. Doing this will hold the rig while still relieving pressure on the locking jaw. Put your vehicle in neutral and turn off your engine.
Chock Wheels and Lower Gear
If your trailer doesn’t have spring brakes, make sure to chock the wheels. If air releases and the emergency brake is released the trailer could move, so chocking the wheels is important, regardless.
Next, you’ll want to lower the landing gear. First, check the gear for any excessive rust, damage or broken welds or components. Ensure both supports are firmly touching the ground. If they aren’t, you may need to go find more level ground somewhere.
If the trailer is loaded down, once the landing gear makes firm contact, turn the crank in low gear for an extra turn or two. This will lift some weight off of the trailer. It will also make it easier to unlatch the fifth wheel and recouple it later. Do not lift the trailer off of the fifth wheel.
Disconnect Air Lines and Unlock the Fifth Wheel
Next, you’ll want to make sure you disconnect the air lines from the trailer. Connect your airline glad hands to the dummy couplers. They should be located on the back of the cab. Make sure they are coupled together.
Then hang the electrical cord with the plug facing down. You do this to prevent moisture from getting into the electrical wiring. Also ensure the lines are supported to prevent damage once the tractor begins to move.
Once the airlines are handled, move on to the fifth wheel. First, lift the release handle lock or safety latch. If you need to use a hook or extension to reach the locking mechanism, do so.
Pull the release handle into the open position. Always remember to keep your legs and feet clear of the rear tractor wheels. If it unexpectedly rolls forward onto your feet, well let’s just say you don’t want that. As always, safety first.
The first in your final steps includes lowering the air suspension. Make sure you slowly drive the tractor forward to clear the kingpin, but don’t pull it completely out from under the trailer.
Release the air pressure bags if so equipped. Once done, release the tractor’s parking brake and pull the vehicle forward until the fifth wheel just begins to clear the trailer’s apron.
Stop just before you clear the trailer, apply the parking brake, put the transmission in neutral and inspect the trailer supports. If necessary, use a trailer safety jack.
Once you are sure everything is safe, release the brakes and slowly drive the tractor clear of the trailer. If the trailer is equipped with air suspension, use it.
With that said, you have officially uncoupled your trailer! We hope you’ve enjoyed this series on coupling and uncoupling your trailer from your tractor. As a professional trucker, you know how important this step is. Safe driving out there.