TM 55-2840-241-23
Figure 5-1. Universal Fittings
5-4. Universal Fittings.
a. Use this procedure to install universal fittings
with backup rings. (see figure 5-1).
(1) Install the nut on the fitting and run it back
until the counterbore of the nut aligns with the upper
inner corner of the seal groove.
(2) Lubricate seals used on oil, anti-icing, and
bleed air tube fittings with lubricating oil (item 7,
table 2-2). Lubricate seals used on fuel tube fittings
with lubricating oil (item 8,table 2-2). DO NOT lubri-
cate seals used on fuel system control air tube fittings.
Install the seal on the fitting.
(3) Work the backup ring into the counterore
of the nut.
(4) Turn the nut down until the seal is pushed
firmly against the lower threaded section of the fitting.
(5) Install the fitting into the boss, making cer-
tain the nut turns with the fitting, until the seal
touches the boss. Then tighten the fitting one and one-
half turns more.
(6) Put a wrench on the nut to prevent its turn-
ning, and position the fitting by turning it not more than
one turn.
5-2
Change 14
