Great Plains 3N4010HDA Operator Manual - Manual (Page 67)

Great Plains Manufacturing, Inc. Table of Contents Index Maintenance and Lubrication 63
2013-09-24 Table of Contents Index 196-444M
Marker Shear Bolt Replacement
Refer to Figure 64
The marker arm is attached to marker body with a pivot
bolt
and a shear bolt . A third clamp bolt acts as a
hold-down for the top of the marker shear base.
The shear bolt is designed to fail if the marker tip gets
hung up on an obstacle. This prevents damage to the
marker.
If the shear bolt fails, replace it with a bolt of identical
size and grade, or one of similar strength.
The supplied bolt is Great Plains part:
802-589C HHCS 7/16-14X2 GR5
This is a 7 ⁄
16
-14 x 2in Grade 5 bolt. If an exact
replacement is not immediately available, temporarily
substitute a metric bolt, M10x0.75 Class 8.8.
Machine Damage Risk:
Do not replace the shear bolt with a higher grade bolt, or the
next obstruction may result in marker damage.
Note: Do not replace the shear bolt with a lower grade
bolt, or smaller bolt, or you may experience nui-
sance shears.
If conditions are causing frequent shears, keep spare
bolts in the storage holes of the marker shear base.
Before installing a new shear bolt, tighten the 5 ⁄
8
-11x5in
pivot and clamp bolts ( , ) just enough so the marker
shear arm moves with some resistance when pushed by
hand.
Note: Repeat the above bolt adjustment step at the be-
ginning of each season.
Figure 64
Marker Shear Base
22514
1 2
3
1 2 3
2
2
1 3