YP-425, 625, 825, & 1025-A3P
Maintenance and Lubrication
87
2018-07-23
401-652M
Marker Maintenance (Option)
See also:
“
Marker Operation (Option) S/N-
” on page 40, and
Marker Shear Bolt Replacement
If a marker gets caught or hits an obstruction, it is
designed to fail a shear bolt
at the fold, pivot on a
second bolt (not visible in Figure), and swing back.
The shear bolt is a hex head cap screw,
5
/
16
-18 x
1
1
/
2
inch Grade 5, Great Plains part number 802-012C,
plus a
5
/
16
-18 lock nut, Great Plains part number
803-011C.
If an exact replacement is not immediately available,
temporarily substitute an M8 x 1.25 Class 8.8 bolt
and nut.
Install a replacement shear bolt on the vertical face on
the side opposite from the pivot bolt. Do not use a higher
grade bolt, or marker hang-ups may result in machine
damage. Do not use a lower grade bolt, or you may
experience nuisance shears.
Marker Grease Seal Cap
If grease seal cap for marker-disk-hub bearings is
damaged or missing, disassemble and clean hub.
Repack with grease and install new seal or grease cap.
Chain Maintenance
Inspect and lubricate chains regularly. The slack of new
chains tends to increase during the first few hours of
operation due to seating.
Chain Slack
Check slack at fixed idlers within the first 8 hours of
operation and tighten idlers as necessary. Check slack at
spring-operated idlers seasonally.
Refer to Figure 96, which, for clarity, greatly
exaggerates slack, and omits the idlers.
1.
Measure the span
for allowable slack:
Locate the longest span of each chain (usually the
span which does not run through the idlers).
2.
Determine the ideal slack:
Long chains (over 36 inch/91 cm):
1
/
4
inch per foot
Vertical short chains:
1
/
4
inch per foot (2.1 cm/m)
Horizontal short chains:
1
/
2
inch per foot (4.2 cm/m).
Figure 94
Marker Shear Bolt
29982
2
1
3
3
Figure 95
Measuring Chain Slack
27264
2
1
