20
VIBRATION
General Information
2. To check front idler height, carefully
move the machine in REVERSE until a
track shoe grouser is directly below the
center of the idler shaft. See Illustration 2.
3. Measure the distance (dimension X),
between the bottom of the track shoe
grouser in full contact with the surface and
the bottom of the track shoe grouser directly
below the idler shaft.
4. Repeat the procedure of aligning the track
shoe grouser directly below the center of the
idler shaft on the rear idler by carefully
moving the machine forward. Measure
dimension X for the rear idler.
5. Idler height varies from model to model
and between front and rear idlers. Compare
dimension X with the recommended nominal
and minimum values for the front and rear
idlers that correspond to your model as
shown in Chart A.
Illustration 3. Measurement points on a soft surface.
Note: In the event that a suitable hard
surface is not available for checking idler
height, a less accurate method may be
used. See steps 6 and 7 below.
6. Carefully move the machine in
REVERSE until a track shoe grouser is
directly below the center of the idler shaft.
7. Stretch a length of string along the top
edge of the track shoes. Dimension X is
measured from the string to the point
where the center line of the idler shaft
intersects the top of the track shoe which is
directly below it. See Illustration 3 for the
location of dimension X.
Illustration 4. Add plates at point Y.
Prior to adding plates under the bogie pads,
raise the machine until the bogies are hang-
ing free. Carefully support the machine. See
the disassembly and assembly module in
your machine’s Service Manual for the cor-
rect procedure.
8. If dimension X is less than the minimum
shown in Chart A, plates should be added
between the lower bogie pad and the top of
the major bogie assemblies at point Y. The
appropriate plates and their part number
are listed in Chart B. See Illustration 4 for
the correct location to add plates.
The addition of one plate installed under a
front or rear bogie pad increases idler
height by approximately 7.50 mm (.295 in).
In order to maintain uniform roller loading,
equal number of plates must be installed
under the intermediate bogie pads. Take
care not to install more plates than are nec-
essary to achieve the proper idler height
dimension. Excessive idler height results in
poor dozer control, particularly while per-
forming finish dozing operations.
Chart B
Plate Plate
Model Part No. Thickness
D8L 9P5543 5 mm (.196 in)
D8N, D8R 7T4699 5 mm (.196 in)
D9N, D9R 7T5422 5 mm (.196 in)
D9L, D10N, 9P2704 5 mm (.196 in)
D10R
D10, D11N, 8P8884 5 mm (.196 in)
D11R