TM-5-2350-377-14-P
ARMORED COMBAT EARTHMOVER (ACE), M9
TECHNICAL MANUAL; OPERATOR'S, UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST) SUPPORTING THE HYDRAULIC BLADE FOLDER-TRACK TENSIONER (HBF-TT)
TM-5-2350-377-14-P - Page 50 of 335
TM 5-2350-377-14&P
GENERAL HYDRAULIC SYSTEM REPAIR METHODS - continued
CAUTION - continued
Do not use TEFLON tape as a sealer on any fittings.
It can separate from the fittings and cause
control valves, relief valves, and actuators to become contaminated and fail.
Failure to comply
may result in damage to equipment.
It is possible to connect a male national pipe thread (NPT) to a female straight thread, but the
fitting will leak.
Learn to recognize the very slight taper which an NPT has (see illustration
below).
Do not attempt to connect NPT and female straight threads.
Failure to comply may
result in damage to equipment.
Do not attempt to use the parts of the 37° flare fitting and the flareless fitting with each other.
The connection will leak.
Use caution when connecting NPTs.
If overtightened, the female pipe thread will split.
If a
connection leaks, disconnect and apply thread sealant.
Reconnect the threads and snug up
with wrench.
Failure to comply may result in damage to equipment.
Do not apply sealant to the first threads of NPT fittings.
If sealant enters the hydraulic system,
it may cause components to fail.
Use caution when installing preformed packings.
Sharp threads can nick the packing, causing
connection to leak.
Failure to comply may result in damage to equipment.
If fitting leaks, check
packing for nicks or cuts and replace if necessary.
Do not overtighten a flareless connection.
Observe torque values on page 0008 00-14.
Overtightening can cause leakage, requiring replacement of entire tube assembly.
When connecting a hose to a fitting, ALWAYS USE TWO WRENCHES.
Use one wrench to
turn the swivel nut onto the fittings, and use another wrench to keep the fitting from rotating.
The following information is provided to familiarize personnel with the various types of hydraulic fittings.
Refer to this
section and the warnings and cautions on the previous page when working on hydraulic systems.
a. National Pipe Thread (NPT).
This thread is commonly found in hydraulic systems.
It differs from other fittings in
that it is tapered.
In order to obtain a proper seal with this thread, you must use a sealant.
The sealant should be
applied to the male fitting.
Torque value guide in this work package, is NOT to be used.
CAUTION
Do not apply sealant to the first threads of fittings.
If sealant enters into the hydraulic system,
it may cause components to fail.
0008 00-9
0008 00
DO NOT APPLY
SEALANT TO
FIRST THREAD
NOTE TAPER
NATIONAL PIPE THREAD (NPT)
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