Pre-trip inspections are a GOOD thing...

Today I spent a lot of time around my home terminal, so I won't bore you with the nonexistent scenery.

When they finally found me a load, it was a quickie--go about five miles, drop my trailer, bobtail* to another lot, pick up a loaded trailer, take it about thirty miles to the customer, and wait patiently to be unloaded. Easy.

So I went about five miles, dropped my trailer, bobtailed to another lot, and hooked up to the loaded trailer. Connected the air lines and the electrical lines, fired up the truck, and walked around the trailer--making sure all the lights worked, that the brake shoes were thick enough (wouldn't do to have them wear out completely in the next thirty miles), etc.

Everything looked good. So I started the truck and pushed in the valve that would feed air into the trailer's brake system.

There was that familiar and comforting (and LOUD) hiss. Excellent.

The hiss continued for several seconds. Not so excellent.

It didn't get any quieter over the next minute or two. Not excellent at all.

I shut down the truck and got out to listen more carefully. The noise all came from one place--near the front pair of wheels on the right side of the trailer. I went back to take a closer look.

(Those who get hopelessly bored by gadget-talk may want to skip this part...)

Tractor-trailers are much too heavy for the kind of brakes you find on a car. Compressed air is (at present) the easiest way to put enough pressure on a brake shoe to do any good. So when you put your foot on the brake, you're actually dumping high-pressure air into a sort of piston arrangement that pushes the brake shoes against the brake drums. HARD.

Each set of wheels has one of these brake actuators. Ten in all--six on the truck and four on the trailer. And one of the ones on the trailer was apparently leaking air. A lot of it. Apparently from some kind of safety valve.

Like I said, a tractor-trailer is HEAVY. Even when everything is working perfectly, stopping one of these things takes lots of room. If the brakes are only working on sixteen of your eighteen wheels, it takes more. This is Not a Good Thing.

(End of boring technical digression)

Fortunately, the wheels all turned.** So I CAREFULLY drove the truck the five miles or so back to the terminal and threw myself on the mechanics' mercy.

It only took them an hour or so to replace the bad actuator and make sure everything else was working. So I got the load to its proper place in its proper time.

Not the most profitable day. But my dispatcher was happy with me--I'd gotten the job done. And the truck was intact. If I hadn't noticed that problem it might not have been.

We're legally required to check a whole lot of stuff on these rigs every day. And every time we switch trailers we're supposed to inspect the new one the same way. A lot of the time you feel like an idiot looking at the same stupid things over and over.

And then there are days like this one.

Which is now over. G'nite.
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*bobtail:
1: (adj) in trucking, refers to a tractor without a trailer.
2: (verb) to drive a bobtail tractor.

**I may have mentioned somewhere that air brakes on a big truck have the same kind of safety system that elevators do. The brakes have powerful springs that hold them against the drums. There's a gadget that uses the air system to push those springs back. So if your air pressure drops too much, the brakes automatically lock up. Good for safety. Not so good for getting the truck to a shop...