Simple steps to follow when hooking up a big rig and trailer.
Step by commercial highway trailers are now by law equipped with maxi brakes. Maxi brakes are a spring controlled brake which sets the trailer brake when the trailer has no air supply when unhooked.
Because of the mandated use of maxi brakes on trailers, I personally do not hook up my air lines to the trailer before pinning up.
Be aware both the driving schools and the DOT testers when testing for your license, insist that you hook up your air lines first before pinning. I feel this is outdated and it is not common practice in the real world of trucking.
Truly if you’re trying to pin up to a trailer and the trailer takes off, you don’t want to be pinned to it anyway. If this happens, the trailer has a brake problem and needs the attention of a licensed mechanic.
Drivers: It’s not your job to be responsible for faulty trailer brakes if you’re not yet hooked up to the trailer.Real world thinking here. Don’t let the shop talk you into moving the trailer for them, especially if you’re an owner operator and it’s your truck. That’s their job. They’re responsible, you are not.
The Process – How I Do It
- I back up and stop the tractor before pinning up to the trailer. I physically get out of the truck and look. I check to ensure my fifth wheel is lined up with the trailer pin, that the trailer isn’t sitting too high for my fifth wheel and that there are no obstructions in the way, such as a trailer pin lock or a fender that may touch while pinning.
- I ensure that I have adequate grease on the fifth wheel, and that the jaws are open. The reason for this is so when pinning up to the trailer, it’s sitting just low enough that the fifth wheel will slide underneath the front edge of the trailer and then slightly pick the trailer up off the landing gear, to ensure there is some weight and pressure on the fifth wheel so it may engage the pin correctly.
If the trailer is sitting too high, you may overshoot the pin.
If the trailer is sitting too low, you may damage a tractor fender or get your drive wheels jammed underneath the trailer.
- When everything looks good, I then get back in the truck and back it up slowly until the fifth wheel engages the trailer king pin and locks.
- The next step is to put the tractor in forward gear and give a little tug forward to ensure the fifth wheel is engaged and locked.
- Then set the tractor brake. Hop out of the truck with a flashlight. Get underneath the trailer and use the flashlight to look at the fifth wheel jaws to be sure they’re both wrapped around the king pin. Check the fifth wheel release handle visually to ensure it is in the closed position.
Now it’s time to hook up your air and electrical lines and do your circle check.
If the trailer passes the circle check, roll up the landing gear, hop in the truck, pull the trailer ahead 15 – 20′ and pull on the trailer brake to ensure the trailer brakes engage quickly and firmly. If so, complete your circle check paperwork and you’re good to go.
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