ROCHESTER HILLS, Mich. (Aug. 16, 2004) — It's summertime and, yes, the living is easy...unless, that is, you're a tire service technician.
If you're lucky enough to be one of the chosen who gets called to service trucks with tire problems on the side of the road at all times of the day and night and in all types of weather, you're probably one busy guy this time of year.
Fifty-one percent of all commercial truck road calls a year are tire-related. Common sense tells you that number has to be higher in the summer when ambient temperatures are high and road temperatures are even hotter. These conditions are very unforgiving to tires that are run underinflated/overloaded. They aggravate a bad tire situation and ensure tire failure.
So naturally tire failures and road calls increase in the summer months. The question is, are your skills and tire service knowledge up to the challenge to get the job done right as well as keep you and everyone else safe? Take this little test and let's see.
So lucky you—you've been assigned the service call to a tractor-trailer rig stuck on the side of a highway in a major metropolitan area at 4 o'clock on a hot, sultry Tuesday afternoon. The air is heavy with moisture and the darkening clouds indicate rain is on its way. Too bad they're not bringing any relief from the heat.
As you approach the truck, you see that it's on the right side berm about three feet off the pavement on a fairly straight and busy two-lane road. No flares or reflective triangles are out—after all, it's just a flat tire in the middle of the afternoon. With your sharp, eagle eyes you spy the tire problem….only the sidewalls remain of the left rear inside tire on the trailer.
So, what's the first thing you do? Correct: Pull over and park your service truck. (Man, you're good!) But where? Got your answer?
The correct Answer (1) is: 30 feet behind the disabled vehicle with the flashers clearly visible to passing and oncoming traffic.
This may not be the most convenient location, but parked here the service truck can be used as a shield to protect you from passing traffic. Parking it closer to the incapacitated vehicle would be more convenient since you wouldn't have to walk so far for your tools. But parking closer leaves no margin of safety between you and the tractor-trailer if someone runs into your service truck. Be sure you are parked so that oncoming traffic can see your flashers and they're not hidden behind the trailer.
What's the second thing you do?
Answer (2): Put on the service truck's parking brake just in case someone does run into the vehicle. This may prevent the service truck from becoming airborne or pushed into the disabled rig and you.
OK, you get out of the truck and go find the driver in the cab of the tractor. What's the first thing you tell him?
Answer (3): “Move your rig!”
The truck to be serviced must be at least five feet from the edge of the nearest traffic lane. If it's not, have the driver move it farther off the road. If he gives you a hard time about moving it, tell him to change the tire himself. Trust me, he'll move the truck. You do not want your butt being a target for rush hour traffic. If someone hits the bull's eye, it's really going to ruin your day!
Now that the truck is a safe distance from the road, what do you do next?
Answer (4): Set up emergency warning devices.
If the truck driver has not done this, it is the responsibility of the technician to do it and protect himself from being injured by passing or oncoming traffic, which, by the way, is getting heavier as the minutes pass.
Where do you put them?
Answer (5): One warning device must be located on the traffic side within 10 feet from the front or rear of the vehicle being serviced. The other two devices should be placed approximately 100 feet from the stopped vehicle in both directions so that they are visible to passing and oncoming traffic on two-lane and undivided highways.
But what if this is a divided highway or one-way road? Where would you put the warning devices?
Answer (6): The warning devices should be placed at the rear of the stopped vehicle—one within 10 feet of the rig, another 100 feet from the truck, and the last one 200 feet from the unit. With this placement, motorists should not be surprised or at least have ample time to react when encountering a breakdown situation.
Now are you done securing the area for your safety?
Answer (7): NO!
What's left to do?
Answer (8): Check to see if the vehicle is carrying hazardous material by checking the placard on the trailer. If it is, inspect the trailer for any visual leaks under the floor and out the trailer door. Tanks on tanker trucks should be thoroughly inspected, too. If you think sticking your head under a trailer to inspect tires in the winter is bad when ice drips down your collar, imagine sulfuric acid or PCBs running down your back.
What else do you check for?
Answer (9): Fuel leaks. If any fuel leaks are found, the truck should not be serviced until the leak is stopped or it has been declared safe by fire or police personnel. (You don't want to discover a fuel leak after you've lit that cigarette you've been dying to have.) But today is your lucky day! No leaks.
OK, now you're ready to get to work. What's the first thing you do before jacking the vehicle?
Answer (10): Inspect the ground under the trailer axles. If it's too soft or not level, the vehicle must be moved to an area where the jacking equipment can be safely located. (Metal plates can be placed under the jacking equipment to prevent sinking in soft ground, too.) Lucky for you, the ground is level. And since it hasn't rained all month, it's hard as a rock under the layer of gravel that covers it.
So, you go back to your truck and get out your tools for jacking the trailer up. What are they?
Answer (11): A jack and a jack stand capable of lifting and supporting more than the actual load on the trailer axle of the disabled vehicle, and two wheel chocks or other suitable blocking material.
Now what's the next thing you do?
Answer (12): Secure the vehicle with the two wheel chocks to ensure that it cannot move in either direction once the axle is raised.
You're now ready to jack up the trailer axle, but where do you put the jack and jack stand?
Answer (13): The safest place to put a jack or jack stand is directly under the axle or any part directly connected to the axle, such as U-bolts or spring saddles.
They should be centered on the axle or lifting point. A vehicle should never be supported by a jack without a jack stand. Soft ground, gravel or the air concussion from passing vehicles can cause a jack to slip and drop the vehicle. Jack stands are intended to provide additional support and safety for you. Use them! Cribbing also may be necessary in some instances to gain additional height.
Now that you've safely jacked the vehicle approximately one inch off the ground, you get your impact wrench and tire tools. What do you do next?
Answer (14): Check the pressure of the outside tire with a service gauge. Since all of the weight on the left rear side of the axle was being carried by the outside tire, check its pressure to ensure it is adequate. If the pressure of this tire is low, it quite possibly is a candidate for a zipper rupture.
Unfortunately, this tire only has 60 psi when it should have 100 psi. What are you thinking now?
Answer (15): “Dear me” (or something like that). You've got a potential zipper rupture on your hands.
So what's the first step in removing the tire assemblies?
Answer (16): Remove the valve core from the outside tire and use a piece of wire to ensure that the valve stem is free from any blockage to deflate the tire. Since the tire has been driven underinflated at 80 percent or less of its recommended pressure, it has to be completely deflated. You can be pretty positive the inside tire is already deflated since it only has two sidewalls.
Where do you do your mounting/demounting and inflation work?
Answer (17): Anywhere, but not be-tween the service vehicle and the stopped vehicle.
Many technicians have been killed when their service trucks were struck by traffic and they were crushed between the two vehicles. They also have been injured and killed when they parked their service trucks close behind the disabled vehicle, leaned the newly mounted tire against the back of the disabled trailer or the front of the service truck and the tire zippered or came off the rim. The air blast knocked them into the other vehicle causing severe bodily harm.
So, remember to park your service truck 30 feet away and never work between the two vehicles. There are good reasons for these rules.
Where do you inflate the tires?
Answer (18): (Which I hope you got right) in a portable safety cage or restraining device. Never sit or lean on the restraining device during inflation unless you want to be knocked into the next county should the tire blow. Always use a sufficient length of hose that allows you to stand outside the trajectory path.
How do you check the outside tire for a potential zipper rupture?
Answer (19): Look and feel for cuts, snags, distortions, undulations, soft spots and broken filaments in the sidewall flex area and listen for popping sounds when rolling the tire.
If you feel, see or hear any of these signs, do not attempt to inflate the tire. If everything seems OK, inflate the tire to 20 psi in the restraining device and check the tire again. If everything still looks good, inflate the tire to 20 psi over the recommended operating pressure. If you hear popping or see distortions or undulations at any time, immediately stop inflation. If the tire exhibits no signs of zipper rupture, reduce the inflation pressure before removing the tire from the safety cage. Stay outside the tire's trajectory at all times.
Well, it is indeed your lucky day! You have safely inflated the two trailer tires and no tire zippered. So what's the next step?
Answer (20): Re-install the tire and wheel assemblies on the trailer using the proper installation procedures. Then get the paperwork signed, put your tools back in your truck and pick up the warning devices.
This was all done safely and without the need to change your shorts. It's now 5 p.m., the trucker is back on the road, it's just starting to rain but it's “Miller time.” Life is good.
So how many of the 20 questions did you get right? Be honest, no cheating. If you got six or less wrong, you passed this test. However, in the real world, if you mess up on just one of these questions, you could end up dead.
Remember: Let's be careful out there—and have a great summer.