PS Magazine - TB 43-PS-558
PS, The Preventative Maintenance Monthly
ISSUE 558
MAY 1999
uilding a strong PM foundation
for your D7G dozer means starting at
the bottom—the undercarriage.
The well-being of all undercarriage
components hinges on good track ad-
justment. If the track’s too tight, it puts
a lot of stress on undercarriage and
drive train components. If it’s too loose,
the track flaps, wearing out roller
flanges and sprocket teeth.
The amount of sag in your track tells
you when to adjust. Measure sag by
laying a straight edge across the top of
the track from the idler to the front
track support roller. If the track sags
more than 1
1
/
2
inches in the middle,
D7G Tractor . . .
Align with mark
Use pin to loosen track
Measure back to
1
/
2
inch
Wear eye protection while pumping
grease, and
never
look directly into
the relief valve. A shot of high-
pressure grease could blind you.
5.
Once the track is loose, place a
track pin or drawbar pin between the
sprocket teeth and the track.
gun to the lube fitting. Pump in grease
until the track idler is as far forward as
it’ll go.
At this point, the track will be al-
most straight between the front carrier
roller and the idler.
3.
Put a mark on the track roller frame,
1
/
2
inch behind the rear edge of the
idler bearing assembly wear plate.
sembly aligns with the mark on the
roller frame.
hm-mm,
looks like
too much
sag
here.
6.
Start your dozer and back it up un-
til the idler backs up
1
/
2
inch or more.
The pin will be at roughly the 12
o’clock position.
7.
Close the relief valve. Connect the
grease gun and pump in grease until
the rear edge of the idler bearing as-
4.
Open the hydraulic relief valve
1
/
6
turn at a time. You can tell if grease is
escaping by watching your track. It’ll
get loose.
it’s time for your mechanic to adjust it.
Here’s how he’ll do it:
1.
Make sure the dozer’s on level
ground.
2.
Open the cover to the track adjust-
ing mechanism and connect a grease
Measure sag here
Pump in grease
Rules to Doze By
Once your dozer’s back on the job,
follow this checklist for a longer un-
dercarriage life:
•
Slow down, especially in reverse.
•
Keep track alignment right on the
nose.
•
Clean mud and debris from the
undercarriage.
•
Use rock guards to reduce wear.
•
Never spin the track.
•
Check for loose or missing hard-
ware. Make sure all hardware is
torqued.
23
MAY 99
PS 558
22
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