PS Magazine - TB 43-PS-631

PS, The Preventative Maintenance Monthly

ISSUE 631

JUNE 2005
PS Magazine - TB 43-PS-631 - Page 4 of 33
V-Packs
The three V-packs on all tanks not equipped with the pulse jet system (PJS) should
be removed, cleaned and inspected after every operation. V-packs on PJS-equipped
tanks are self-cleaning.
•
Eyeball the bead on the front face of
each V-pack element for dents or sharp
edges that could cut the plenum box seal.
Then check for buckling on the rear face
of the element. Either problem means
you need a new V-pack.
•
Look for broken welds and cracks in
the plenum air box. Dust trails along the
welds and seams of the box are a good
sign of a leak, so tell your mechanic.
•
Look for torn, cracked or missing plenum box seals. A missing seal makes your
tank NMC.
Those three seals also deteriorate over time, so check each one by measuring the
depth of the depression made by the V-pack bead in the seal. If the depression meas-
ures more than 3/16 inch, get the plenum box seal replaced.
1.
Apply chalk to
the raised portion of
the V-pack bead.
2.
Install the V-pack
and secure the hold-
ing clamp.
3.
Remove the V-
pack and eyeball the
plenum box seal.
There should be a
complete chalk line
around the seal from
contact with the V-
pack bead.
If the chalk line is broken, the V-pack may not be sealing
correctly. So, get your mechanic to install a new seal, NSN
5330-01-098-6807. Remember to wipe the chalk off the V-pack
bead and seal after testing.
This method works especially well if you are putting new
V-packs in without replacing the plenum box seals. But, it’s a
good idea to put in new seals along with the new V-packs
whenever possible.
Skirt Seals
If you’re having problems with clogged air cleaner intake filter elements
(V-packs), missing fender skirt seals could be the cause. Those rubber strips are
there to seal the area between the skirts and hull.
Missing seals let dirt and dust
get sucked inside the fender
skirts. The engine pulls the dirt
into the intake system where it
clogs up the V-packs.
All the seals are important, but
pay special attention to the seals
at skirts 4, 5 and 6 on the left side
of the vehicle. These seals are
closest to the air intake grills and
can let in the most dirt.
NSNs for the seals are listed in Figs 261-264 and 266 of TM 9-2350-255-24P-1
(Oct 92) for the M1, Figs 263-266 and 268 of TM 9-2350-264-24P-1 (Sep 01) for
the M1A1, Figs 242-245 and 247 of TM 9-2350-288-24P-1 (Jul 01) for the M1A2
and Figs 241-244 and 246 of TM 9-2350-388-24P-1 for the M1A2 SEP (Feb 01).
The preferred cleaning method is
the V-pack cleaning wand. You’ll find
info on the wand in the “unusual con-
ditions” section of your -10-2 TM’s
operating instructions.
PS 631
JUN 05
4
If the cleaning wand isn’t available,
shake the V-packs, making sure not to hit
them against anything harder than your
hand. Brush dirt and dust from the ele-
ments with your hand. Then, have the
elements properly cleaned by your unit
maintenance folks as soon as possible.
Use wand to
clean V-pack
No
wand?
Shake
V-pack
gently
While the V-packs are
out, inspect the plenum
box and elements for
potential problems…
I got a
new seal
for the
tank!
Here’s
another
way to check
the seals…
Chalk placed here…
…should
show up here
Look for dents or buckling
631.04-05(C)
4/29/05
3:05 PM
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