TM 1-1500-204-23-9
(a) Before tightening, be sure that all threads,
sealing and mating surfaces are clean and free of nicks,
burrs, and scratches.
(b) Install fittings (except as specified below) with
antiseize compound, Federal Specification TT-S-1732.
1 Install hydraulic system fittings using
hydraulic oil as both a lubricant and antiseize
compound.
2 Use thread compound, MIL-T-5542, as both
an antiseize and a sealing measure while installing
oxygen system fittings.
(c) Get the proper size open-end wrench with 15-
degree offset heads to snug the nut.
NOTE
The snug (no torque) condition is reached
when, using an open-end wrench, a
positive increase in resistance (on the
nut) to turning is felt (greater than run-on
torque), when parts appear to be properly
seated, and when no looseness between
mating parts is noted.
(2) Tightening to 15-degree wrench arc. Proceed as
follows:
(a) Using an open-end wrench, snug the nut.
(b) With wrench still positioned on nut, establish a
line of sight using wrench handle, as shown in figure 8-
24.
(c) Use angular difference between handle and
wrench flats (15 degrees) to visually measure amount
that nut will have to be turned.
(d) Turn wrench until flats on nut (engaged by
wrench) are aligned with line of sight established by
handle in figure 8-24.
(3) Alternate method for tightening to 15-degree
wrench arc. Proceed as follows:
(a) Using an open-end wrench, snug the nut.
(b) With wrench still positioned on nut, use
engaged nut flats to establish a line of sight, as shown in
figure 8-25.
(c) Turn wrench until handle is aligned with line of
sight.
(4) Tightening to 60- or 120-degree wrench arc. In
this method of tightening, primarily used for tube fittings,
the flats on the union are used as a reference.
Wrenches other than open-end wrenches (crowfeet or
tubing wrenches) may be used. Proceed as follows:
(a) Using an open-end wrench, snug the nut.
(b) Use the corners of coupling nut and of mating
union to gauge amount that coupling nut will have to
move, as shown in figure 8-26.
(c) Turn coupling nut 1 flat for 60 degree wrench
arc.
(d) Turn coupling nut 2 flats for 120 degree
wrench arc.
(5) Tightening to 30-degree wrench arc. Proceed
as follows:
(a) Using an open-end wrench, snug the nut.
(b) With wrench still positioned on nut, note
position of wrench handle, and pick out point of
reference in line with handle, as shown in figure 8-27.
(c) Invert wrench using same nut flats. Angular
difference between center-lines of wrench in the two
positions is 30 degrees.
(d) Turn wrench to position established in figure
8-27.
(6) Tightening to 90-degree or 180-degree wrench
arc. In this procedure, wrenches other than open-end
(box, tubing, crowfeet) may be used. Any local
reference, such as the engine or component centerline,
may be used to judge wrench travel.
(a) Using an open-end wrench, snug the nut.
(b) For 90 degree arc, turn wrench until handle is
perpendicular (at a right angle) to its starting position, as
shown in figure 8-28.
8-12
