PS Magazine - TB 43-PS-580

PS, The Preventative Maintenance Monthly

ISSUE 580

MARCH 2001
PS Magazine - TB 43-PS-580 - Page 4 of 32
PS 580
MAR 01
5
PS 580
MAR 01
4
echanics, before you start work on the electrical system of M998A2-series
HMMWVs and the M1113/M1114/ M1123 vehicles in the family, completely dis-
connect the batteries.
These vehicles have a dual voltage system. That means disconnecting
both
neg-
ative battery cables, not just one. If you attempt electrical system work with even
one negative cable still connected, you risk component damage and severe shock.
So disconnect the system using the info found in Para 4-73b, TM 9-2320-280-20-2,
for the M998A2-series and M1123 trucks, and in Para 4-68b, TM 9-2320-387-24-2, for
the M1113/M1114 vehicles.
Full details are found in TACOM Maintenance Advisory Message (MAM)-00-
012,
HMMWV 24-Volt Electrical System (Jun 00)
.
ome maintenance shops estimate that 90 percent of the repairs they make to
HMMWV soft-top doors are for torn window zippers.
And how do those zippers get torn? Grit and sand gum up the works so that zip-
pers don’t slide easily, for one thing. For another, the thread used to install the zip-
pers dry rots quickly.
So when a little extra muscle is used to budge a sticky
zipper, the whole thing often rips loose from the door.
Here’s the best thing to do to prevent damage:
x
Remove grit and sand caught in the zipper teeth
with an old toothbrush. Then lube the teeth with zipper
lube. NSN 9150-00-999-7548 gets you a box of 24 lube
sticks. The lube is Item 29 in the Expendable/Durable
Supplies and Materials List in TM 9-2320-280-10.
x
Run a little zipper lube over the threads that hold the
zipper in the door, too. That’ll help keep the threads from
drying out and rotting so fast.
How often you have to clean the zippers and lube them
depends on where your HMMWVs are located. If there’s
lots of sand around, it may be more often than the month-
ly check and lube shown as Item 75 in the -10’s PMCS.
Just make sure the lube’s used before strong-arm tactics.
HMMWV.
..
580. 04-05 (C)
1/29/01
9:40 PM
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