PS Magazine - TB 43-PS-680

PS, The Preventative Maintenance Monthly

ISSUE 680

JULY 2009
PS Magazine - TB 43-PS-680 - Page 9 of 33
14
PS 680
JUL 09
Dear Editor,
While performing wheel maintenance on our HEMTT, we discovered a
problem. Paragraph 12-2 in TM 9-2320-279-20-2 covers the wheel
and drum assembly wheel bearing and stud removal and installation for the
number 1 and 2 axles. On Page 12-8, the TM says to tighten down the
locknut to 100 lb-ft, loosen
1
/
2 turn, and retighten to 50 lb-ft using the
wheel bearing wrench.
Here’s the question we had: How do you torque the locknut down when
there is no place for a torque wrench to attach to the tool?
Our solution was to weld an adapter to the end of the bearing nut
socket, NSN 5120-01-279-4789. And use a
1
/
2 drive torque wrench.
Your readers can benefit from this tip.
Editor’s note:
Thanks for the tip,
Sir
. Readers, make a note of this. Also,
Page F-33 in Appendix F of TM 9-2320-279-20-3, (Apr 87, w/ Ch8, Jul 05), gives
fabrication instructions for the socket, which is a similar solution. The fabrication
uses bearing nut wrench, NSN 5120-01-279-4789, and gives instructions to weld a
plate with an opening for a torque wrench to the socket. TACOM says the current
socket, PN 3335074 and NSN 5130-01-520-9330, has a square drive end.
Bob Vinyard
QA/Maintenance Coordinator
TACOM Transportation Support
Ft Leonard Wood, MO
C
ross-country driving can have a bad effect on your M989A1 HEMAT trailer.
Brush smacks against the side of the trailer, hitting the air tank valves. That can
actually knock open the valves and drain out the air. No air means no brakes or
locked spring brakes on the rear wheels.
So when you hit the back country, take a quick look at the trailer’s air tanks during
stops to make sure the valves are still closed.
HEMTT…
Fab Fabrication for
Wheel Bearing Wrench
M989A1 HEMAT Trailer…
Don’t Brush Off Air Tanks
Check air tank valves to ensure they are closed
Take bearing nut socket,
NSN 5120-01-279-4789, and…
…weld an adaptor to the end
of it so it looks similar to this
How do they expect me
to torque the locknut
down when there’s
no
place
for a torque
wrench to attach to
the bearing nut!?
We’ve got the
answer. All
it takes is…
…a little bit
of
welding!
Side view
Top view
680.14-15.indd
1-2
6/9/09
4:44:35 PM
B.V.
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