TM 5-2350-377-13&P
0051
GENERAL HYDRAULIC SYSTEM REPAIR METHODS - Continued
CAUTION
ALWAYS clean around fittings before disconnecting or connecting hoses or fittings.
Ensure area is clean before installing hydraulic components. Failure to comply may result
in damage to equipment.
Cover, cap, or plug all openings, ports, and tube or hose endings when disconnected.
Failure to comply may result in damage to equipment.
Ensure fittings are connected to fittings of the same design or damage to equipment may
result. Connecting unlike fittings may not damage threads, but is not a guarantee that the
connection will not leak.
Fittings must be installed and tightened. If a fitting cannot be tightened, it may be cross-
threaded or have damaged threads. Failure to comply may result in damage to
equipment. Use wrench only for final tightening.
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 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 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 at end of work package.
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.
RELIEVING HYDRAULIC PRESSURE
NOTE
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.
Refer to TM 5-2350-262-10.
1.
0051-2
03/15/2011Rel(1.8)root(maintwp)wpno(M00034)
