Runaway big rig on Calif. highway hurts 10 - Life- msnbc.com
27 Injured in Big-Rig, Multi-Car Grapevine Crash - NBCBAYAREA- msnbc.com
Yes, there is a reason I posted this here.
If you lose air pressure, the spring brakes take over. You're going to stop. But Lebec, CA is on top of the Grapevine. I checked the Weather Channel and did not find what the temps were. The air temperature could well have been a factor in the failure of the brakes. 120 psi, brakes are released, and you're ready to roll. Then a situation arises and you apply brakes... Nothing. You STAND on the brakes...
NOTHING!!!
No, I do not know that this is what happened, but if it did, and they take the truck down the mountain to check out the brake failure, they may find nothing wrong. The brakes may work just fine and be completely normal.
Compressing air causes water vapor to condense. The air dryer is supposed to remove all the moisture from the compressed air so that it does not collect in the tanks and lines. However, like anything made by man, it's not 100% effective. If it was, you would not have to worry about draining the tanks, and there would be no provisions for you to do so. But, that moisture does not always collect in the tanks.
Milwaukee, WI, about 3 years ago. My air dryer was working normally, but I lost air pressure. With a temp of 10 degrees outside, I was under the hood trying to figure out what went wrong. When I disconnected the pressure line from the compressor, the compressor was working. Yet, that pressure was not getting to the air dryer. Eventually, I found the cure to the problem was a dose of AIR-LINE ANTI-FREEZE in the pressure line, at the compressor. In about 10 minutes, I was ready to put all the air lines back on and get back on the road. After putting the AIR-LINE ANTI-FREEZE into the line at the compressor, I had chunks of ice coming out of the hose at the air dryer.
I've also had trailers that would not release the brakes. Last winter, I left FL and everything was working fine. When I got up into KY, I found that when I came to a stop at a light, and held the brakes for a minute or more, the trailer brakes would not release when the light turned green. Again, a dose of AIR-LINE ANTI-FREEZE cured the problem, and the brakes released just fine.
No, I have any idea what the temps were at the top of the Grapevine at the time. But, considering the altitude and the season, it may have been cold. With heavy fog conditions, it could have meant the air dryer was over-worked, but more likely, there had already been water in the air lines. All it takes to trap some water in an air line is a sag for the water to collect in. While running in warmer temps when closer to sea level, there would have been no problem. But if the temps at the top were below freezing, the water could have frozen solid. The driver could have been standing on the brakes, but the lines would have been blocked, and no brakes would have been applied.
About once a month, I take off the pressure line from the compressor and put about one shot-glass into the line. That works through the tractor to keep the moisture liquid in cold weather. And, if I know I'm going into an area where the temps are going to be below freezing, I put a shot glass of air-line anti-freeze into each glad-hand when hooking to my trailer. So far, that is all it has taken to keep everything working fine.
So, was that the problem at the top of the Grapevine? I don't know. I do not know what the temps were at the time. But I have had brakes fail to activate because of ice in the line.
Years ago, when I was driving an International COE with spring suspension, (1989) I had an occasion when the brakes would not apply. Not something you forget easily. 3 AM, and you come to a stop sign. No ice on the road, but no matter how hard I pressed on the brakes, the rig just kept on rolling. I managed to get stopped on the shoulder (after the stop sign) by popping the buttons, and setting the brakes. After that, no matter what I tried, I could not get the brakes to activate.
Another truck pulled up behind me, and the driver could have been in his sixties or seventies. He asked what the problem was, and when I told him, he went back to his truck and brought back a bottle of alcohol. We jacked up the cab, and put a dose into the pressure line, at the compressor. About fifteen minutes, and everything was working normally.
If that was the problem on top of the Grapevine, one ounce of alcohol (air-line anti-freeze) would have been very cheap insurance.
Runaway rig injures 10
