PS Magazine - TB 43-PS-578
PS, The Preventative Maintenance Monthly
ISSUE 578
JANUARY 2001
echanics, you know to use geared
hub lockwashers only once, then throw
them away. But do you know there
may be faulty lockwashers on your
trucks or in your stock?
TACOM Safety-of-Use Messages
(SOUM) 00-014 and 00-017 called at-
tention to lockwashers that are too
thick to bend properly into the locknut
slots. The tabs are also more likely
to crack at the bend. The messages
deadlined HMMWVs that had not
been inspected and had replacement
lockwashers installed.
So you should know and you should
have complied. Here’s why:
Using these lockwashers increases
the chances that the locknut will loosen
and come off, which could cause a
wheel to fall off.
HMMWV . . .
To use another lockwasher to test, match
a tab on it to a tab on the lockwasher
installed on the truck. If the installed
lockwasher is thicker than the good one,
replace it. If the installed lockwasher is
the same size or slightly thinner, it’s ser-
viceable and can be left on the vehicle.
The only other alternative to the inspec-
tion procedures is to replace all lock-
washers with known good ones.
For details, get your hands on both
SOUMs from your local TACOM logis-
tics assistance representative.
You can use a known good lock-washer
instead of the hex head wrench for test-
ing, but you must know the lockwasher is
a good one. You can’t just guess.
3.
Look for cracks or breaks at the
tab bends. If you find any cracks or
breaks, replace the lockwasher with
a new one, NSN 5310-01-213-4185,
that is 0.090 (+/–0.010) inch thick.
4.
If there are no cracks or breaks,
measure the lockwasher’s thickness
using a
7
/
64
-in hex head wrench. If
the lockwasher is as thick or thicker
than the hex head wrench, replace
it. If the lockwasher is thinner than
the wrench, it is serviceable.
If you have not complied with the
inspection criteria found in the SOUMs,
or you’re not sure if your vehicles are
using the right lockwashers, here’s what
to do now:
1.
Remove each wheel assembly, drain
the geared hubs and remove the steer-
ing arm covers.
2.
Clean the lockwasher tab surface
and ensure that the bent tabs are flush
against the surface of the locknut slot.
Drain geared hub
i sure
did
, and i
took care
of it!
hey! did
you know i could
have a
bad
lockwasher
in my
hub
, bub?
Check tabs
Compare with good lockwasher
Check lockwasher thickness
PS 578
3
JAN 01
PS 578
2
JAN 01
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