3D-MC: Basic Training - Weekly Maintenance Grader

Suggestions for weekly grader maintenance

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3D-MC: Basic Training - Weekly Maintenance Grader


The Topcon control system does not change. However the machine on which the system is mounted does.  Motor Graders/Dozers and Excavators all have wear edges that require replacement over time.  As the cutting edges or bucket teeth wear, the operator may encounter an elevation error. On machines with cutting edges, not only will the elevation be affected by the wear, but as the cutting edge wears, it can also induce a slope error. 

Typically, once the hydraulics are set, they do not require any adjustments.  However over time, due to mechanical wear or hydraulic services, fine tuning may be required for optimal performance.

The GPS antenna mounting on Motor Graders is designed to be removed during transportation. Due to the design, it is possible to reinstall the GPS antenna differently, unless the install was done using locking collars to ensure the antenna is reinstalled the same way.

The Motor Grader has three sensors to measure the blade position (Rotation, Mainfall, and Blade slope sensor). Over time, through normal usage, as the machine wears, the three sensors may need to be recalibrated to maintain accuracy.  Within the Topcon software, a calibration routine is available that will walk the operator through the system calibration.

As the cutting edge wears, the height of the GPS antenna to the cutting edge will shorten, causing a consistent elevation error.  Within the Topcon software, there is a blade wear calibration that will compensate for blade wear.

Blade Trim

  • The “Blade trim” adjusts for the uneven wear of the blade, which results in an error in the slope.
  • In this process, grade a finish pass traveling in one direction, and turn the machine around, verifying the grade matches in the opposite direction.


  • Blade trim first pass:
    • Set the desired slope in the slope box and turn either the left or right side in auto.
    • Manually control the opposite side and grade a pass, ensuring the entire moldboard carries a load of material, leaving a consistent grade.
    • Press the Next button at the end of the pass. This will invert the slope for the next pass.
  • Blade trim matching pass:
    • Turn the machine around and drive over the previous pass with either the left or right side in auto.
    • Lower the side in manual until it touches the previous grade.
    • Using the arrows on the screen, adjust the side in automatic until it matches the previous pass
  • Blade trim complete:
    • The value displayed in the Blade slope adjustment window indicates the slope error.
    • Press Finish to save the blade trim value.​

Calibrate Sensors

  • Calibrate Sensors: is a built-in routine that will walk an operator through an entire series of sensor calibrations.
  • After performing the blade trim calibration, if an slope error is experienced, one of the other sensors may need to recalibrated.​
  • Blade Rotation:
    • This first calibration will set the Rotation calibration to 0 deg.
    • With the machine on smooth consistent grade, rotate the blade to the calibration marks that were put on the circle during the installation.
    • Press Next after aligning the calibration marks.

First Blade Position:

  • In this step the system will perform the first step of the Blade and Mainfall calibration.
  • Rest the blade on the ground and mark the location of the edges of the blade.
  • Press the Next button.​
  • Second Blade Position:
    • In this step, the system will compare the blade slope and mainfall slope from the previous step to determine the amount of error.
    • Place the blade on the marks from the previous screen, ensuring they are in the same location.
    • Press Next.
  • Displayed are the calibration adjustments that will be saved once you press Finish.
  • Always confirm calibrations are correct by using the system to grade in one direction. Turn around and verify that the grades match in the opposite direction.

Blade Wear

  • As the cutting edge wears, the distance of the GPS antenna to the cutting edge will shorten, causing a consistent elevation error.  Within the Topcon software, a blade wear calibration indicator exists, which will compensate for blade wear.
  • When the system is initially installed, the operator enters all the required dimensions.
  • As the cutting edge wears, measure the distance from the center of the bolt that holds the cutting edge to the end of the blade.
  • This will adjust for all blade wear.