TM 55-2840-231-23
Do not remove wrappings, protectors or covers until the part is ready to be installed.
1-51. Hardware.
Use 0.020 in. diameter stainless steel lockwire (item 7, Appendix D) where lockwire size is not specified.
Double strand lockwire all drilled bolts, plugs, and screws, except those locked with self-locking nuts or
lockwashers. Lockwire bolts in pairs where possible. When reassembling, be sure to safety wherever lock-
wire was removed. Do not use zinc lockwire. Do not reuse lockwire, cotter pins, ring seals, lip seals, com-
position gaskets, and split or tabwashers.
1-52. Universal Fittings.
a.
Use this procedure to install universal fittings with backup rings. (See figure 1-18.)
(1) Install the nut on the fitting and run it back until the counterbore of the nut alines 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 5,
Appendix D). Lubricate seals used on fuel tube fittings with lubricating oil (item 4, Appendix D). DO NOT
lubricate seals used on fuel system control air tube fittings. Install the seal on the fitting.
(3) Work the backup ring into the counterbore 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 certain 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 turning, and position the fitting by turning it not more
than one turn.
(7) Hold the fitting in its position and tighten the nut against the boss.
b.
Use this procedure to install universal fittings without backup rings. (See figure 1-17.)
(1) Run the nut on the fitting end back until the washer face is alined 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 5,
Appendix D). Lubricate seals used on fuel tube fittings with lubricating oil (item 4, Appendix D). DO NOT
lubricate seals used on fuel system control air tube fittings. Place the seal in the seal groove.
(3) Screw the fitting into the boss until the seal barely touches the boss.
(4) Turn the fitting and nut together until the nut touches the boss.
(5) Put a wrench on the nut to prevent its turning, and position the fitting by turning it in up to
270 degrees or unscrewing it up to 90 degrees.
(6) Hold the fitting in its proper position and tighten the nut against the boss.
1-135
