Great Plains PD8070 Operator Manual - Manual (Page 37)

1/24/2006 401-266M
35 Maintenance and Lubrication
Replacing Shear Pins
Refer to Figure 29
The cotter pins (1) that connect shafts to transmission
will shear when an excessive load is put on the shafts.
Infrequent or improper lubrication causes binding of
moving parts within the planter. This binding will cause
cotter pins to shear, thus preventing breakage of planter
parts.
Check for binding by turning drive shaft with all seed
hoppers installed and seed meters engaged. If drive
shaft is hard to turn, disengage one seed-meter clutch
at a time to find the problem clutch.
Improper shaft alignment can also cause pins to shear.
Refer to Shaft Alignment, page 35.
When drill shaft can be turned freely by hand, replace
the cotter pin.
IMPORTANT: Replace cotter pins with cotter pins of the
same size. Do not replace with other type pins.
Shaft Alignment
Refer to Figure 30
Improper shaft alignment can cause pins to shear. To
function properly, transmission shafts must be aligned
and level. If the planter is consistently shearing pins,
follow these steps to check and adjust the shafts.
1. Check that transmission input shaft (1) and trans-
mission shaft (2) are aligned. Remove cotter pin
from coupler sleeve. Pull coupler sleeve back and
observe the shafts.
Refer to Figure 31
2. If shafts are not aligned, adjust contact-drive tower.
Loosen mounting bolts (1) on both sides of tower.
Adjust tower position until shafts are aligned.
3. Retighten tower mounting bolts. Slide coupler
sleeve over transmission input shaft and reinsert
cotter pin.
Contact Drive Spring Tension
Refer to Figure 32
The contact drive spring tension is preset between 1” to
1 1/4” at the factory. Occasionally, due to planting
height or planting conditions, it may be necessary to
adjust the spring tension to keep the contact drive tire
from slipping.
Adjust tension until contact drive tire has enough ten-
sion to stay in contact with gauge wheel. NOTE: DO
NOT increase tension so much that contact drive
tire resists turning.
16862
Figure 29
Transmission Cotter Pins & Shear Pins
16832
1
2
Figure 30
Transmission Input Shaft Alignment
16849
1
1
Figure 31
Contact Drive Housing Adjustment
Figure 32
Contact Drive Spring Tension (Factory Setting)