Trailer Brake Fire

I'm still a student, but I'll weigh in on this one since it was covered in class. Our instructor told us that after completing the brake check, let the unit roll on a level surface and see if it rolls freely to a stop - so that you can find one or more brakes that may be dragging. He also told us that when checking the slack adjusters, make sure that they are not adjusted TOO tight - less than about 3/8" (if I recall correctly) is asking for problems. If and when the brakes heat up, the expansion can be enough to allow them to drag, creating more heat, more dragging, etc.

 

Well you sure had an exciting time. Seriously, I hope you remember the smell. Burning brakes and rubber. Now that is very distinctive.
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I have no idea how long you were driving before the [bleep] hit the fan. Possibly if you had stopped to do a walk around the truck after 1 or 2 hours of driving, you would have gotten some idea of the problem. Maybe not. While not trying to make fun of your misfortune, it provided an invaluable education.
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Flatbedders have a practice of stopping a short time after starting on route to recheck their load securement. The same practice may be valuable for the rest of us to check the brakes when we pick up a different trailer.

 

Good idea in the drop and hook world, as your starting out let out the clutch and get the truck rolling. Push the clutch back in and coast. Should roll free. Also if in winter weather and parking for the night, after you have parked, roll the truck a few feet in one direction before you set the brakes. I would strongly suggest you not dump the trailer supply (red button). After you roll free zig zag looking in your mirrors to insure the trailer tires are turning.

 

Had similar happen to me one time with my co-driver. Hauling cars thru MS and we had a 4 wheeler waving us down. Co-driver looked in mirrors, I looked in mirrors and saw nothing. But the 4 wheeler wouldnt leave us alone. My co-driver wanted to ignore the guy and I kept telling him to roll the window down to find out what was up. The 4-wheeler then sped up and moved in front of us while another 4-wheeler came along side waving us down too. Well the 4-wheeler infront kept braking on us! WTF, so finally he pulls the truck over. The people in 4 wheeler run up to truck screaming fire! LOL
We both grab fire extinguishers running to back of truck and the trailer tires on pass side are on fire with a car/gas tank directly above it. Well we got fire out really fast! Thank goodness but then hear comes the town fire dept. They roll up from a frontage road along the highway, jump the fence, spray water on the smoking tires for like 2mintues.
We got a bill from that little town for the fire dept help. $1500 !!! Man was my co-driver pissed!
Yes it was a break that was held up and it was below freezing and raining at the time.

 

You got a tire fire out with portable extinguishers?

 

We sure did!

 

Do ol' crusty Hammer a favor, and if you ever see that instructor again, kick him square in the boys for feeding you such garbage as this. Following his logic, brakes should be more effective the hotter they get! When brakes get hot, two things happen: The drum expands away from the shoes, and the friction material loses it's effectiveness. Now it is true that brake material is most effective at temperatures above ambient; but a dragging shoe is going to blow right thru that optimal temp range rather quickly.

My guess (for the little it's worth...) would be someone in the recent past had pulled that trailer with a defective air dryer. Line froze up at some point in your travels, and most likely the heat of the fire thawed it back out.

 

That's often what happens, applying the brakes causes the transfer of air, and the moisture it contains. Plus you have a pressure drop, and any supercooled droplets would flash to ice when that happened.