Well it’s been a lively day here. South of town there’s a gravel pit and after a climb into the valley, it’s about a 3-4% downhill grade from there through town. Highway 36 is also our Main Street. A semi lost it’s brakes just as he was coming into the South end of town and came flying down Main Street, hitting 27 cars and ending up crashing into the Ford Dealership. Dude did a pretty decent job of steering clear of traffic. Several people injured but nobody killed.
"...if the gentlemen of Virginia shall send us a dozen of their sons, we would take great care in their education, instruct them in all we know, and make men of them." Canasatego 1744
A lot of people don’t think about it this way, but there are truckers who are heroes. Machines fail and the trucker often keeps people from getting hurt, often to their own demise.
Many years ago I was driving north bound coming down the Siskiyou Summit on I-5 and moved over to let a semi fly by with fire coming out of his front wheels.
Lose the engine, lose the air compressor, lose the air brakes. Every semi I've driven had an emergency brake lever next to the steering wheel. Pull it and everything locks up. I haven't driven one in 25 years, though, so I can hardly say what's in a modern tractor.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
I wondered the same. They’re illegal in town but if you’re out of options who cares. I’m sure the Highway Patrol and UDOT will have a lot to say about it. Wondering if he got the trans in neutral and couldn’t get it back in gear for some reason or snapped a U joint and threw the driveshaft; damaging the air lines.
Definitely tore things up. Kilgore, well their insurance, is going to be writing quite the check. We’re up to 33 vehicles now.
That wouln't do much, but there is a large, yellow, diamond shaped, button on the dash that should have stopped the truck by locking up all the brakes on all the wheels a long way back up the hill.
You can see the smoke pouring out of the truck. When facing a long downhill, the driver has to downshift prior to hitting the downhill. In this case he probably wanted 6th gear. You let the transmission keep you slow on the hill.
If you leave it in tenth gear, the truck will go too fast, and you have to try to slow down with the brakes. The brakes will catch fire, and the brakes will fail, and then, you have a runaway truck.
Properly adjusted brakes are a huge deal, but modern trucks can certainly lose brakes even if they started out adjusted properly. Losing brakes is an affect of getting hot, not too much slack. Unevenly adjusted brakes can accelerate problems due to individual brakes heating faster, then failing. Leaving more burden to the remaining brakes.
Shutting a diesel off does nothing. The hold back effect of a gas engine is pumping loss. It's the effort of drawing vacuum, caused by closed throttle plates. Diesels don't have throttle plates. The throttle directly controls fuel, not air movement.
The brake lever by the steering wheel (looks a bit like an automatic gear selector) does not "lock everything up". It's simply a hand brake that controls the trailer brakes only. On straight trucks it controls the drives and any lift axles. It uses the same air as the foot pedal, in the same way. Except it only actuates the trailer brakes. Mostly, it's used to lock the trailer axles to slide tandems or 5th wheels.
A lot of company spec trucks don't have them. Guys use them instead of the service brakes. Over taxing the trailer brakes and ruining them.(using them for anything other than sliding stuff is controversial)
As to the brakes locking due to low air? Pulling the yellow button?
Both are the same thing, one automatic, one driver activated. Usually, if they automatically deploy, the button pop's out. Sometimes, there is a small psi range where the brakes apply but the button doesn't pop.
That braking system is simple spring powered. Pushing the yellow button supplies air to an actuator that compresses the springs and releases the brakes. If the button is pulled or air pressure lost, the actuator disengages and strong springs apply the same brakes normally used. But not with anything like the power of the air system. A heavy truck rolling at some speed, downhill, is very likely to NOT be stopped by the spring brakes.
Jake brakes can and do fail, not often. Transmissions can jump out of gear. On old mechanical engines, that usually shut the engine off. Losing the air compressor and power steering. There is no way to get back in gear until the engine is running. If the truck accelerates to a speed higher than It's governed at, it's impossible to get a gear even if the engine starts.
There are numerous possibilities here, the service glad hand popping off is certainly a possibility.
One thing I will bet the farm on. It's not one issue. Accidents are almost never a single failure.
Usually in something like this you will find, Speed Brake Maintenance Brake adjustment Other mechanical failure Air loss (maybe tied to other causes, especially maintenence) Over loaded To name a few.
By the time DOT is done, they will have a list.
If he was overloaded, the quarry may well be involved. The one I hauled out of refused to let us leave heavy. Following a wrongful death lawsuit that they were involved in. Selling an extra ton of stone cost them dearly.
Last edited by Dillonbuck; 11/04/23.
Parents who say they have good kids..Usually don't!
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