PS Magazine - TB 43-PS-714
PS, The Preventative Maintenance Monthly
ISSUE 714
MAY 2012
17
PS 714
MAY 12
S
mooth operation is the “name of the game” when it comes to the guide rollers
behind the scraper’s bowl. Here are two areas that need your attention when you
grab the grease gun.
The top and bottom guide rollers behind the scraper’s bowl are out of plain view
because of their location. Each roller moves back and forth when the bowl is loaded
or emptied. Without lube, a roller locks up and drags along its guide track. The end
result is a lot of wear and tear to the roller, bowl and ejector.
Don’t let that happen to your scraper. Lube the grease Fttings on the bottom rollers
with a grease gun during scheduled services.
But there are no Fttings on the top guide rollers! So, once a year, remove the access
cap on the top guide roller. Use a ½-in socket wrench to remove the four cap bolts.
You’ll need a pry bar to hold the guide roller in place while turning the bolts with
the wrench.
Pack the access cap and
the guide roller’s bearing
with GAA. By the way,
there’s nothing that tells you
to lube the top guide rollers.
That’s because the info is
missing from the scraper’s
lube order! So hold on to
this guidance.
S
omething as simple as an upside down nut can knock your track off.
Mechanics, the dozer’s track shoe nuts have a
rounded side and flat side. When a track shoe nut
is installed upside down—with the rounded side
against the track shoe—vibration will loosen the
nut. That could lead to a thrown track.
To keep that from happening, always install the
flat side toward the shoe.
It’s not enough to get the nut on
right.
You also have to get the nut
tight
enough.
For the D7-series, tighten the nuts to 220 lb-ft, then give them another one-half turn. For
the D8K, tighten the bolts to 250 (+/- 50) lb-ft, then give them another one-half turn.
621B Scraper…
Guide Rollers Need
lube!
D7G, D8K Tractors…
Track Shoe Nut Info
Install flat side of nut toward shoe
Use
1
/
2-inch
socket wrench to
remove cap bolts
Pack roller
bearing
with GAA
Remove
cap
oh,
nuts!
nuts is
right!
you must have
installed my
track shoe nuts
upside down!
without
lube, I’m
a real
drag!
you’re
telLing
Me!
714 16-17.indd
1-2
4/2/12
5:30 PM
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