TM 1-1500-204-23-2
any appreciable torque to fitting Maximum wrench tor-
ques, in inch-pounds, for fitting nuts on various sizes
and types of tubing are shown In table 4-2.
j. Installation of Beaded Tubing. Beaded tubing Is
used In low-pressure applications using rubber hose
and hose clamps (see figure 4-16).
(1) Proper sealing of hose connections. To
prevent breakage of hose clamps and damage to hose,
Instructions on tightening hose clamps shall be followed
carefully. When available, use any approved torque
wrench to torque hose clamps as per (2) or (3) below,
Figure 4-16. Installed Low-Pressure Hose
depending on the hose type. In the absence of a hose
clamp torque wrench, the fingertight-plus-turns method
shown in table 4-3 should be used. Due to the variance
in hose clamp design and hose structure, values given
in table 4-3 are approximate and care should be exer-
cised when tightening clamps by this method.
NOTE
Aircraft hose constructed with synthetic com-
pound has tendency to cold flow. Therefore,
when new hose is installed, clamps should,
after a period of time, be retightened in order
to maintain original torque value. This Is
caused by synthetic rubber flowing from
under clamping area and not from loosening
of clamps
Table 4-2. Hydraulic Tubing B-Nut (AN818) Torque Values
Torque on tube nut
Tube outside
Aluminum alloy
Steel tubing
diameter
tubing
1/4 Inch
40-65 Inch-Pounds
135-150 Inch-Pounds
5/16 Inch
60-80 Inch-Pounds
180-200 Inch-Pounds
3/8 Inch
75-125 Inch-Pounds
270-300 Inch-Pounds
1/2 Inch
150-250 Inch-Pounds
450-500 Inch-Pounds
5/8 Inch
200-350 Inch-Pounds
650-700 Inch-Pounds
3/4 Inch
300-500 Inch-Pounds
900-1,000 Inch-Pounds
1 Inch
500-700 Inch-Pounds
1,200-1,400 Inch-Pounds
4-13
