PS Magazine - TB 43-PS-732
PS, The Preventative Maintenance Monthly
ISSUE 732
NOVEMBER 2013
12
PS 732
NOV 13
Use a 0 to 6-in vernier caliper to measure the area and thickness of each cleaned
corroded area. The vernier caliper is included in the standard automotive tool set
(SATS), NSN 4910-01-490-6453.
The original thickness of the upper coupler plate is .375 inches. The kingpin
coupler weldment must measure .319 inches or more for the upper coupler to
be usable.
This table will help you Fgure out the extent of corrosion deterioration and loss
of material thickness:
When overall thickness is less than .319 inches, the upper coupler isn’t repairable
and the tanker is deadlined. You’ll have to remove and replace the king coupler
weldment to bring your tanker back to a fully mission capable (±MC) status.
And when overall
thickness is .319 inches
or more on the upper
coupler, it’s serviceable,
but you still need to take
a few corrective steps.
±irst, remove all
corrosion and old paint.
Next, treat and repaint
the area following the
spot painting guidance
in TB 43-0242,
WD
CARC Spot Painting.
Then insert drainage
holes in the kingpin
coupler weldment.
Here’s where those
drainage holes should
be located:
W
henever you transport fuel tankers, it’s important to be safe. Otherwise, you and
others near you could have a
really
bad day. So here’s a problem with M900-series fuel
tankers that you
must
know about to keep yourself and others safe while hauling fuel.
A recent inspection found too much corrosion around the upper coupler plate and
frame structure. Corrosion build-up weakens the frame structure and can cause the fuel
tanker to separate from the prime mover. But you can prevent this from happening.
If your unit has M967A1, M967A2, M967P1, M967A1P1, M967A2P1, M969A1,
M969A2, M969A3, M969P1, M969A1P1, M969A2P1, M969A3P1, and M970A1 fuel
tankers, inspect each vehicle. TACOM SOUM 13-008 gives you details on what to do.
It’s available at:
Upper Coupler Inspection
Unbolt and lower the kingpin coupler weldment from the tanker
following the instructions in the TM that supports your model. That
allows you to inspect the kingpin coupler weldment and the tanker’s
main frame structure.
Remove any rust or paint ²akes on the kingpin coupler weldment.
That’ll help you determine the actual amount of deterioration.
Upper coupler
plate
Upper coupler
support cross
members
.375
.338
.319
.188
.563
.250
.225
.213
.125
.375
Component
Original
thickness
(inches)
10 percent
loss
(inches)
15 percent
loss
(inches)
50 percent
loss
(inches)
150 percent
repaired thickness
(inches)
M900-Series Fuel Tankers…
wait,
wait! don’t
leave me!!
Here’s what the safety message has
to say about controlling corrosion
on your unit’s fuel tankers…
I shoulda known
corrosion would
separate us!
For M967A2 and M969A3
models, drill six
5
/
8
-in holes in
kingpin coupler weldment.
1’ 1
1
/
8
“
2’ 11
7
/
8
“
11“
1’ 10
3
/
4
“
2’ 8
5
/
8
“
Corrosion
Could
Deadline
Your Vehicle
732 12-13.indd
1-2
10/2/13
12:55 PM
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