PS Magazine - TB 43-PS-631
PS, The Preventative Maintenance Monthly
ISSUE 631
JUNE 2005
PS 631
JUN 05
16
Lunette-type Trailers…
Don’t
Have a
Shackle
Fit
W
hen your tactical
vehicles get heavier
towing
shackles
to
comply with air trans-
port regulations, your
trailer safety chains will
need larger hooks to fit
over them.
Forget the easy way out, like putting smaller shackles on the trucks so your old
chain hooks will fit. That defeats the purpose of the safety chains.
Replace the old chain hooks with a larger one, NSN 4030-01-438-1803. That
hook works on the larger shackles and is easy to install.
Cut the trailer chain’s last link or remove its removable link. Discard the old hook
and install the new one with its pin and cotter pin.
M939-Series Trucks…
Steady at 40 MPH Speed Limit
D
rivers, the highway speed limit is still 40 mph unless your M939-series 5-ton
truck has the MWO 9-2320-272-55-1 applied.
TACOM Safety-of-Use Message (SOUM) 00-
018 (Jul 00),
Resumption of Safe Operating Speeds
for M939 Family of Vehicles Following Retrofit of
Anti-lock Braking System (ABS)
, authorizes you to
resume normal operating speeds only after MWO
9-2320-272-55-1 is applied.
Application of ABS to your trucks rescinds the
requirement for MWO 9-2320-272-20-7 and
removes the brake proportioning valve installed
during that modification. Never add MWO -20-7 to
a truck that has been modified by MWO -55-1. It’s
not needed then.
Trucks with the ABS MWO have a yel-
low triangular decal with black lettering
“ABS” in the lower left corner of the wind-
shield. Of course, there’ll be a regular
MWO tag on the cab reinforcement just
inside the driver’s door, too.
MWO 9-2320-272-20-7, which
still has not been applied to some
vehicles in the fleet, installed a
brake proportioning valve kit to
prevent front-wheel lockup during
heavy braking when driving on
slick surfaces with little or no load
on-board.
TACOM SOUM 98-07 (Apr 98),
Safe Operating Speeds for M939
Series Trucks,
dropped speeds to
40 mph and outlined safe driver
practices. It is still in effect until
MWO -55-1 is installed.
ABS
MWO
APPLIED
MWO 9-2330-372-55-1
DATE JUN 9 05
Look for decal on windshield…
…and MWO plate
on door frame
Heavier towing shackles…
…need new chain hooks
don’t use me like
this!
you need a
bigger hook!!
kid, I’m writing you
up for going
over
40 mph
without an
abs sticker.
631.16-17(C)
4/25/05
4:55 PM
Page 1
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