PS Magazine - TB 43-PS-579

PS, The Preventative Maintenance Monthly

ISSUE 579

FEBRUARY 2001
PS Magazine - TB 43-PS-579 - Page 12 of 33
M198 Towed Howitzer . . .
T
wo new special tools that are now
available make servicing your M198
howitzer a whole lot easier. One is a
nitrogen intensifier and the other is an
oil transfer system.
Nitrogen Intensifier
The operating pressure for the M198’s
equilibrators is 1,750-1,800 psi.
Elevating the tube with pressure less
than 1,750 psi is difficult, but it’s next to
impossible with pressure under 1,500
psi.
That means when it’s time to charge
the equilibrators, you have to use a nitro-
gen cylinder with at least 1,500 psi.
When the cylinder pressure drops below
that reading, your unit must pay to have
it recharged.
You can save time and money by using
a nitrogen intensifier, NSN 1025-01-
473-8886. When it’s hooked up to a par-
tially-used cylinder, the intensifier draws
out most of the remaining gas and
increases it to the proper psi.
Oil Transfer System
The M3 oil pump is currently used for
filling and purging air from the M45
recoil mechanism. The M3 holds about 1
quart of hydraulic fluid. The M45 recoil
mechanism holds about 6 gallons.
It takes around 70+ pumps of the
M3’s handle to move the oil reserve
indicator from one number to the next.
So completely filling and purging the
recoil takes a lot of time and wears out
quite a few arms.
The new oil transfer system, NSN
1025-01-473-7710, puts a stop to that.
It has a 5-gal reservoir and an electric
pump that makes filling and purging the
recoil a snap.
The system self-purges all air from its
lines before pumping oil and includes a
Nitrogen intensifier,
Oil transfer system,
Once the pressure reaches 150 psi or
less, the cylinder has to be recharged.
special filter that screens out all contam-
ination. Make a note until both new tools
can be added to Fig C-75 of TM 9-1025-
211-20&P.
PS 579
FEB 01
20
PS 579
FEB 01
21
579. 20- 21 (C)
1/11/01
1:33 PM
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