PS Magazine - TB 43-PS-634
PS, The Preventative Maintenance Monthly
ISSUE 634
SEPTEMBER 2005
SEP 05
13
M989A1 HEMAT Trailer…
M915,
M915A1,
HEMTT…
Lock
Up
Back
Up
s
Air Dryer Kit
P
ulling the HEMAT trailer is easy stuff, drivers, as long as
you pay attention when making turns. Backing one up is
another story.
Before you start, you need to get out of your truck and
lock the trailer’s towbar in place. A lot of drivers forget, or
figure they’re good enough to maneuver an unlocked trailer.
They’re the red-faced ones who have to explain the dam-
age to the trailer and the back of the truck when the trailer
jackknifes.
So make sure you lock the towbar every time before
backing the trailer. Just remove the hitch pin, raise the lock-
pin handle, rotate it counterclockwise to the short slot, and
replace the hitch pin. Then get a couple of ground guides to
help you back up.
If the hitch pin and chain are missing, replace them with NSN 4010-01-353-9428.
You can also order the parts individually.
The pin comes with NSN 5315-01-098-
6455 and the chain with NSN 4010-01-353-9368.
When you’ve finished backing, unlock the towbar so you don’t forget when it’s
time to move out again.
Servicing the air
dryer on big trucks
doesn’t
mean your
unit has to spend
big bucks.
Some mechanics service
the dryer by replacing
the entire canister.
instead, clean the
dryer by using a
desiccant parts
kit,
NSN 4440-01-
081-1391.
The kit has
everything
you
need—including
instructions—to make
the air dryer as
good as new.
Forget that—you’re
just
throwing money
down the drain.
Move lockpin handle from open…
…to locked position before backing
I’m locking
the trailer’s
towbar
before
backing up!
whew!
that’s a
relief!!
I dunno…
seems like a
lot
of money
to pay for a
new air dryer
cannister.
you can
service the old
one with a
kit!
I learned
my lesson
the last
time!
soldier,
stop!
634.12-13(C).qxd
7/29/05
2:03 PM
Page 1
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