by Steven Easley

Created on: August 28, 2008   Last Updated: November 07, 2008

Professional Truck Driver
Back to Basics: Coupling

This is one of the first in a planned series of instructional articles pertaining to the job of the professional truck driver. These articles are not intended to imply the only way of performing a task. Their purpose is to aid in training new drivers and provide a refresher for experienced drivers. I hope you find the information both useful and enjoyable.

Step 1: The first step to coupling (joining) a combination vehicle is to back the tractor under the trailer. Here are a few tips to help make this a little easier. Using the flat mirror, line the outside of the tire up with the outside edge of the trailer, back up slowly until you see the trailer lift slightly, you should also be able to feel the rear of the tractor squat down under the added weight of the trailer. As you're moving back pay attention to the location of the front mounted mud flaps in relation to the nose of the trailer. Once the rear axle is under the trailer you should notice the lift and squat, if not stop. Set the tractor brakes and take the truck out of gear and get out and inspect the trailer height. It may be necessary to dolly down the trailer so that the kingpin doesn't pass over the top of the fifth wheel. If this occurs you'll have to either dump the tractor air bags or use the trailer's landing gear to raise the trailer above the fifth wheel or a combination of the two.

If you have observed the lift and squat then it is no necessary to stop and inspect the trailer height. One school of thought however, is that the driver should connect the air line and electrical pigtail prior to backing completely under the trailer. The reasoning behind this is that there is additional working room for the driver to connect the hoses and cable and that in this fashion the trailer is connected to the air brake system. This is not the case as the trailer braking system supplies air to release the brakes and when the trailer is not connected the brakes are already locked into place against the hub. For the purpose of this article, it is not required to stop.

Now, referring back to the position of the front mounted mud flap, as you continue to back up you will notice that the mud flap moves closer to the nose of the trailer. You can use this as a reference point to prevent slamming the kingpin against the fifth wheel locking device. As you creep backwards, remember to have your driver's side window open so that you can listen for a distinctive click sound.

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