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. This audible click is the result of the locking jaws inside the fifth wheel clicking into place around the kingpin. Next pull forward slightly with the tractor so that it tugs on the kingpin. The purpose of this is to insure that the combination vehicle is properly secured. Simply, you want to hear the click then tug on the trailer. ekspedisitermurah
Step 2: Connect the gladhands, (the air line connectors) and the electrical pigtail. The best way to do this is to begin at the furthest point and work toward you. The gladhands are color coded on both the air lines and the nose of the trailer. Connect the blue, service line, first then the electrical pigtail and finally the red, emergency line. Each of the gladhands has a rubber gasket inside; these should be inspected each time you connect to a new trailer. If these gaskets are worn or damaged replace them immediately, because they will not seal properly and you’ll lose air pressure to the braking system.
Step 3: Raise the landing gear, which is commonly referred to as the dolly. The landing gear is equipped with a handle and a gear box. The gear box has a high and low speed as well as a neutral. To change gears you have to either push or pull the handle in or out, on the shaft that runs through the gear box. The position for high and low gear is not universal and varies from one trailer to the next, even within models built by the same company. Start with the gear in low and crank the handle to raise the landing gear until it either clears the ground surface or at least turns freely. Depending on the position of the trailer the legs are subject to scoot along the ground. Once you’re able to switch to high gear, continue raising the legs until they are they are fully retracted. Using high gear will save you time and energy, rather than cranking the legs up in the much slower low gear. If you decide to spin the handle to make it easier, be watchful of the hand grip as it can cause injury to your head and face. Once you’ve completed dolly up the landing gear, return the handle to its holder, this is help to prevent damage to the handle and possibly passing vehicles, although striking another vehicle isn’t very likely. The handle holder also may be bend and therefore not hold the handle securely, so check it whenever you stop. Retracting the landing gear legs fully will help to prevent getting your trailer stuck on railroad crossing or other areas where you may encounter poor road surfaces.
Remember these three simple steps: (1) Click and Tug, (2) Connect (3) Dolly-up so that you don’t have to deal with driving away from your trailer and leaving the nose in the dirt.