UNDERCARRIAGE
MODEL
12
D
CRAWLER
2.
Track
Assemblies
Track
Frames
Periodically check the track frames
for
loose bolts.
The entire assembly should
be
steam
cleaned
to
allow
for
a close inspection.
The track assembly may
be
removed from the
undercarriage
by
removing the twelve mounting
capscrews and the
two
stop brackets which fasten
it
to
the carbody.
NOTE:
Each
track
assembly
weighs
approximately
20,000
lbs.
(9000 kg).
Use
a hoist or
crane
capable
of
supporting this weight.
Track Rollers
Both the upper and lower track rollers
are
sealed
and
require no periodic lubrication. They should,
however,
be
checked regularly
for
leakage,
free
rotation and wear.
Periodically check the torque on the roller mounting
capscrews.
Keep
lower roller capscrews torqued
to
560
lb-ft
(760 Nm).
To
extend the life
of
the rollers,
if
excessive
wear
is
noted in one particular location,
the rollers may
be
rotated. Switch the rollers that
show the least wear with those
that
show the most
wear.
NOTE:
The roller nearest the drive sprocket end
is
larger
in diameter than the rest, and
can
not
be
re-located.
The upper carrier rollers
are
held
suspended
by
clamp-type mounts welded
to
the track frame. The
clamp bolts should
be kept torqued
to
65
lb-ft
(88
Nm).
18
Track Chain
and
Pads
A total
of
50 links
are
used
per track. Each
link
will
accept one track pad. The
pads
are
made
of
cast
alloy, and
bolt
to
the track links
with
four
bolts each.
The
pads
can
be
removed
from
the chain
without
removing the track. Simply remove the
four
mounting bolts.
NOTE:
When
replacing or switching
pads,
make
sure
the
pads
are
installed with the lower lip facing
in
the
normal direction
of
travel.
The track
pad
mounting bolts should
be
kept torqued
to
560
lb-ft
(760Nm). Loose mounting bolts
will
cause
unnecessary vibrations and
pad
wear.
Each
track chain consists
of
forty-eight standard links
and
two
master links. The master links
can
be
identified
by
the indentation on the end
of
the
link
pin. The master
link
is
equipped
with
an
extra set
of
spacers
which allows
it
to
be
removed more easily
than the standard links. A portable
press
is
required
to
remove the track pins.
MASTER
PIN
Figure 22. Master Link and
Pin
Track Tension
Proper track tension
is
important.
If
the track
is
too
loose,
it
will
tend
to
jump
the drive sprocket and
kink
between the rollers.
If
it
is
too
tight,
it
will
cause
excess
wear on the track
link
pins and bushings.
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