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General Information
VIBRATION
• Checking the Balance of the Machine
• Adjusting the Height of Center
Tread Idlers
Procedure to Determine
Idler Height (D8L, D8N,
D8R, D9L, D9N, D10, D10N,
D11N Tractors)
Model Applicable Serial Numbers
D8L All
D8N All
D8R All
D9L All
D9N All
D9R All
D10 All
D10N All
D10R All
D11N All
D11R All
As track roller tread wear and damage,
deterioration or loss of bogie pads occur,
and excessive machine vibration may
result. This vibration is the result of insuffi-
cient idler height. Idler height is the distance
that the tread of the track idler is above the
tread of the adjacent track roller. See Illus-
tration 1 for the area to be measured.
Illustration 1. Idler Height.
Under typical operating conditions, wear
causes the diameter of the track roller treads
to decrease at approximately twice the rate
of the track idlers. When the front or rear
rollers reach approximately 70 percent wear,
the idler height may approach the minimum
recommended value. Variations in operat-
ing conditions influence the wear rates.
Additionally, the installation of new or
rebuilt idlers on machines with partially
worn track rollers directly affects idler
height.
To measure idler height, use the following
procedure.
Illustration 2. Measurement points on a hard surface.
1. Move the machine to a hard, level sur-
face. Inspect to make sure all bogie pads are
in place. If any pads are missing or unser-
viceable, they should be replaced.
Chart A
Front Idler Front Idler Rear Idler Rear Idler
Model Nominal Minimum Nominal Minimum
D8L 29 mm (1.142 in) 17 mm (.670 in) 34 mm (1.339 in) 10 mm (.394 in)
D8N, D8R 15 mm (.591 in) 10 mm (.394 in) 16 mm (.630 in) 10 mm (.394 in)
D9L 23 mm (.906 in) 11 mm (.433 in) 27 mm (1.063 in) 11 mm (.433 in)
D9N, D9R 24 mm (.945 in) 11 mm (.433 in) 21 mm (.827 in) 11 mm (.433 in)
D10 25 mm (.984 in) 14 mm (.551 in) 32 mm (1.260 in) 12 mm (.472 in)
D10N, D10R 26 mm (1.024 in) 14 mm (.551 in) 23 mm (.906 in) 12 mm (.472 in)
D11N, D10R 32 mm (1.260 in) 14 mm (.551 in) 23 mm (.906 in) 12 mm (.472 in)