Applications and Innovations: Cool graders
Brooke Wisdom | May 1, 2010
By Mike Anderson
On most jobsites, the grader operator is king.
Nobody dares get in his way … and, should anyone need to tell him anything, such a task is left to only the most senior of supervisors. The “blade hand” is staunchly independent, often gruff, and yet universally admired and respected. Rarely is there another equipment operator within 50 miles who can, be it with traditional lever or breakthrough joystick in hand, feel his way from rough ground and raw material to the glass-like smoothness that will cradle the office buildings, parking lots and roadways to come.
It stands to reason, then, that the king’s carriage is maintained with discipline and order, whether it be driven through snow or dust, be it tasked with winging back drifts on a blizzard-closed township road in Minnesota or carving through barren hardscrabble in west Texas.
With the summer work season underway, there are some particular maintenance issues to keep in mind.
“The obvious difference between winter and summer months is the ambient temperatures. In the past, you had to be more conscious of the outside temperature because the cooling package design may not have been as efficient as it could have been and you didn’t want to overheat and damage your engine,” says Bryan Abernathy, vice president of Champion Motor Graders, a manufacturer of compact and mid-sized grader models.
Today’s emissions-restricted engines run at even higher temperatures. “This change,” says Abernathy, “means grader manufacturers and engine suppliers must work closely together to design cooling packages to keep things at optimum temperature. To withstand the harshest of conditions like Australian, South African or even our own California summers, manufacturers who sell graders globally must design for the most extreme conditions. Even though 95 percent of the world may get a cooling package that is over-designed for their climate, the extra capacity doesn’t mean good maintenance practices can be relaxed.
“Summer brings dryer ground conditions, which produce more dust. There is also more activity on jobsites, which unfortunately means more trash which will eventually find its way into the screens and fins of the grader’s cooling package. Leaves, candy wrappers and those plastic grocery store bags can easily make their way into the cooling package, creating a blockage and restricting proper air flow for cooling. Most service trucks carry an air compressor, so as part of your daily maintenance, you should blow out the coolers in the opposite direction of normal air flow. Look for debris stuck in the cracks and crevices of your engine compartment.”
In its 35-plus-point safety and maintenance checklist specific to motor graders as part the extensive www.safety.cat.com website, equipment manufacturing giant and grader industry stalwart Caterpillar notes that daily machine inspections must include checking the restriction indicator on the air filter. Caterpillar offers the largest range of motor graders, ranging 12 to 24 feet in blade width, 138 to 533 horsepower in net engine output, and 31,069 to 137,694 pounds in base gross vehicle weight.
In a DVD issued by Volvo Construction Equipment for owners of its full-sized G900 Series motor graders, the message is emphasized with a warning: “Inspect the air filter housing and exhaust aspirator hose for damage. Do not open the filter housing unless the air filter restriction indicator light is illuminated. Unnecessary opening and closing of the air filter housing only creates an opportunity for contaminants to enter the engine.”
Among the unique features of the motor grader is that its work tool, the blade, is mounted mid-machine. Before the grader is driven away to begin moving dirt for the day, what should be a set daily walk-around for operators includes some specific inspections focused on the drawbar area, according to Volvo:
Inspect the moldboard slide rails for damage and remove any debris that may be present;
Inspect the moldboard cutting edges for wear, damage or loose bolts;
Inspect the timing gear and drive pinion gears for damage and debris; and
Inspect the drawbar ball stud for damage.
Beyond daily routine requirements, the DVD details service, adjustments and inspections required at 10, 50, 250, 1,000, 1,500 and 2,000 hours. For the drawbar area, maintenance comes to the fore at the 50-hour mark. Moving around clockwise, starting from the cab door, the service professional is advised to:
Lubricate the blade lift cylinder ball pins;
Lubricate the circle turn cylinder and crank bearing;
Lubricate the circle turn valve driveshaft bearing;
Lubricate the circle shift cylinder bearings;
Lubricate the blade shift cylinder bearing; and
Lubricate the moldboard tilt cylinder bearings.
In addition to proper washing of the cooling package, advises Champion’s Abernathy, “keep your graders clean everywhere, especially around fuel and oil fill points. And make sure whoever is doing your fuel and oil fills has clean equipment and tools! If their equipment is dirty, foreign particles can easily be transferred into your fuel or hydraulic system.
“It’s not always the hot summer temperatures that cause the problem,” he says. “During the construction season, equipment and people are kept busy. It increases the chance of human error, which can result in a costly repair.”
And, of course, you can never forget about the king.
“Finally,” says Abernathy, “you need to take care of the most important component of your grader – the operator.
“Motor grader operators take great pride in their skilled trade and in the equipment they operate. If they identify something that needs attention, then as the owner you should correct the issue as soon as possible,” he says. “We have seen this happen a number of times: When a small problem is ignored, operators tend to be less diligent with the equipment. Over time, this attitude creates larger problems. Hotter temperatures bring hotter attitudes to the jobsite and, if the operator thinks that you don’t care, then they will stop caring, too.
“The best way to get the most from your grader is to make sure that everything is in perfect working condition, especially the air conditioning.”v
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