PS Magazine - TB 43-PS-557
PS, The Preventative Maintenance Monthly
ISSUE 557
APRIL 1999
PS 557
18
APR 99
Raised Ramp = Low Level
C
rewmen, don’t try to get a reading from the ramp hydraulic reservoir on
M113-series vehicles until the ramp is all the way down, as your LO says.
A partially lowered ramp will
always
cause a low reading. If you add more
hydraulic fluid—bringing the level to
halfway in the sight glass—you end
up with too much.
That overpressurizes the system.
Then, hydraulic lines blow and you’re
stuck with a big, messy problem—not
to mention a ramp that won’t move.
Lower the ramp
all the way
—then
check the sight glass. That’ll give you
an accurate reading.
M113-Series FOV . . .
After torquing the bolts, drive the ve-
hicle forward about 100 feet and then back.
Recheck the torque and tighten if neces-
sary. The initial stress of operation some-
times loosens the bolts slightly.
Once the marks are made, crew-
men can make sure the marks line
up during PMCS. Spotting a loose
bolt is easy this way.
Of course, the best solution is to
keep the bolts from coming loose
in the first place. Try these two tips:
Before you torque the bolts, take
a close look at how the tapered
washers under the bolt heads are
installed. Make sure the tapered end
Mark line across bolt and shaft hardware
Tapered end of washer fits against prop shaft
there!
that
takes care of
the
prop shaft
bolts
!
now that's
a real
work
of art
!
?
?
With ramp
down, fluid
should be
halfway in
sight glass
of the washer goes against the prop shaft
or U-joint. Otherwise, the bolt works loose.
ost of the damage caused
by loose or missing propeller shaft
and U-joint bolts on M113-series
carriers can be prevented by crew
checks before each mission.
Spotting a missing bolt is easy
enough, but how does the crew
check for tightness?
That’s where you mechanics
come in. When you pull semi-
annual PMCS, torque all the bolts.
Then make alignment marks on the
bolt heads and prop shaft or U-joint
yoke. Mark them with paint or with
a scribe or awl.
PS 557
19
APR 99
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