Importance of blade shimming and maintenance [VIDEO]

Importance of blade and circle shimming on motor graders

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Importance of blade shimming and maintenance [VIDEO]

What happens when your blade shims are not properly maintained?

Take note of the points in the video as the operator rotates the circle and moldboard cylinders.

You will see multiple points at the cylinder knuckle, circle table, and the moldboard slides that have excessive slop or play in them.

These areas should not exhibit this play and must be shimmed by a qualified heavy equipment technician.

Failure to keep the machine shimmed, with good cutting edges on the machine, will result in poor automatic grading performance. 

Slide rail brass

The slide rail also has brass shims which will need to be replaced as they wear out. 

As seen in this picture, a significant gap is observed, allowing the moldboard to have excessive play in the vertical and roll axis. 

Circle wear plate and shims

There are also wear plates between the circle and turntable which must be shimmed occasionally.

Hose tray

Another important area to maintain is the hose tray guide rods.

When the guide rods present any play, this will have a direct result on the rotation sensor accuracy.


Correct clearance for hose tray guide rods

The rods should only have enough clearance to freely move with circle rotation, as shown in the image. 

When your machine is not tight, your grade won't be tight.

When the machine is not properly shimmed, the direct result is seen on the ground with wavy or choppy grade.

Your grader hydraulics will act as though they are constantly hunting for grade due to the excessive play in the knuckles, slide, and circle turntable. 

Note: If you notice any of the symptoms, have a qualified heavy equipment technician replace the wear pads, brass, and/or shims as needed.