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Motor graders require a little more care than other pieces of heavy iron to ensure they can maintain precise grades. “Considering that finish grade is typically from 1/8 to 1/4 in., turntable and moldboard slide tolerances must be maintained as close as possible,” says Phil Newberry, market development engineer, motor grader marketing, Caterpillar. “Once wear reaches or exceeds these tolerances, it makes it extremely difficult to achieve grade in a productive fashion.”

Regular maintenance helps prevent excessive wear on critical moving interfaces. “Grease points are by far one of the most important maintenance items on a motor grader,” says Woody Ferrell, vice president of sales and marketing, Champion Motor Graders. “Motor graders have more moving joints and implements than most any other type of construction equipment. “

This requires vigilant record keeping of the service intervals. “Stay within the recommended service intervals stated by the manufacturer for all serviceable items, not just engine oil changes,” says Ferrell. “There are other wear items that get overlooked, because the service technicians get used to performing a standard type service or the customer cannot have any extended downtime. Therefore, the customer will only allow the minimal service so he can keep working the motor grader.”

Yet, there are areas that require more attention. “The most common wear points are the blade slide guides, circle guide shoes on the turntable and blade lift cylinder connections,” says Keith Lee, research and development, LeeBoy. “Any play in these areas allows the blade to move — 1/16th in. in two, three or four places can add up quickly.” This is known as tolerance stack. You start adding play in all of the critical joints together and pretty soon the whole system is loose.

Maintain tolerances

The tighter you can keep the components, the better. “Tightness in the moldboard slides, circle supports, drawbar ball stud and even the operator’s seat are all important factors to consider when determining if the grader can produce a finish grade to the tolerance specified,” says Brian Lowe, product and communications manager - motor graders, Volvo Construction Equipment. “As the accuracy of most machine control systems are checked at least daily, if not more frequently, so too should the critical areas of the circle and moldboard slide be inspected.”