PS Magazine - TB 43-PS-562
PS, The Preventative Maintenance Monthly
ISSUE 562
SEPTEMBER 1999
621B Scraper . . .
Tire PSI Reminder
Check the scraper’s tire pressure be-
fore operation. Front tires get 60 psi
and rear tires get 40 psi.
Low front tires may slip on the rim,
causing ’em to overheat and blow out.
Or the tire-to-rim seal is broken and
the tire goes flat.
When you have a flat front tire, you
may lose the driver—that little piece
Torque
planetary
gear cover
nuts to
65-85 lb-ft
Then, open the manual drain cock of
the scraper’s rear air tank behind the
scraper’s bowl. Because of its location,
this tank is the one that’s usually
missed. Make sure all the drain cocks
are closed when you finish.
Drain front.
..
Battery box pads in place?
Blow out dirt before it gets packed
...and rear air tanks
Torque
carrier
cover stud
nuts to
235-295 lb-ft
I
can dig
it!
PS 562
23
SEP 99
PS 562
22
are in place. The pads keep the battery’s
clamp, post connections and the box’s
support rails from touching the access
door.
Without the pads in place, the
batteries can short out. If a pad is
torn or missing, your mechanic can
replace it with NSN 9320-00-060-9363.
Keep the pads in place with cyano-
acrylic adhesive, NSN 8040-00-142-
9193. This NSN will bring you ten
1-oz bottles.
Dirt and sand settle around the bat-
teries in the box. When the dirt gets
wet and packed in, the batteries are a
bear to get out. Clean out the box if it
needs it.
Torque Talk
The nuts on the 621B’s front wheels
take different torques.
Too much torque on the planetary
gear cover will put the squeeze on the
O-ring underneath. Then the O-ring
will leak oil. Low or no oil means the
bearings will burn out.
perators, even a workhorse like your
621B scraper needs some TLC to keep
it scraping.
Follow the operator info in TM 5-
3805-248-14&P-1 and use these PM
tips to keep your scraper mission-ready.
Battery Box Lowdown
Check the batteries during weekly
PMCS.
With the battery box open, make sure
the foam pads on the box’s access doors
of metal that ties together the final drive
and the side ring. Without it, there’s no
way to deliver power to the wheel. Get
a new driver with NSN 2530-01-060-
4345.
Drain Air Tanks
A drop in temperature increases
condensation in the scraper’s air brake
system. Condensation leads to corro-
sion, slow stops, and brake failure.
After each day’s operation, open the
manual drain cocks of the two air tanks
near the cab step (curbside).
Since you won’t find the
torque values in the TM, use these:
hey!
we could
use a
good
cleaning
in
here!
?
Replace lost drivers,
NSN 2530-01-060-4345
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