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TM 10-3930-643-20
GENERAL MAINTENANCE PROCEDURES. (cont)
2-12.
Application of Adhesives. (cont)
c. Loctite Retaining and sealing Compounds. These compounds will resist
solvents, heat, shock and vibration.
They provide a positive seal against
leakage and sheer strength resistance to loosening when used in the assembly of
threaded, slipfit or press fitted parts.
Use the grade of Loctite specified.
Once cured, these compounds have an operating temperature range of -65 to 300
degrees F (-54 to 149 degrees C), and will resist attack by oils, chemicals,
hydraulic fluids and solvents.
Do not use Loctite where other retaining means
are provided, such as lock wires, lock washers, lockplates and fasteners. Do
not substitute grades or usage unless specified.
Do not use Loctite on items
that need frequent servicing, brass fittings or plugs, or when
operating
temperatures exceed 300 degrees F (149 degrees C). (Example:
Engine
exhaust
systems.)
Loctite is applied as follows:
(1) Threadlock adhesives.
Loctite MIL-S-46163, Type II, Grade O, a high
strength adhesive for fasteners and Loctite MIL-S-46163, Type 1, Grade L, a
high viscosity, high strength adhesive for large bolts and studs, are recom-
mended for use on this vehicle.
Primers are not
required
with threadlock
adhesives, but if used will speed up the cure and act as a
cleaner.
Surface
preparation depends on type of metal and purpose of application.
I n g e n e r a l,
most surfaces must be cleaned thoroughly.
Apply Loctite to bolts and studs by
filling full length of thread with one strip in diameters up to 1 inch,
two
strips, 180 degrees apart, on diameters up to 2 inches, and three strips,
120
degrees apart, on diameters over 2 inches.
Apply one strip into tapped holes.
For blind hole applications, apply enough Loctite to fill the bottom 2 to 3
threads of engagement, then insert stud.
If engagement length exceeds one
diameter,
use proportionally more Loctiteo
For non-seated studs (studs that go
deeper in hole than required) turn stud one turn deeper than required.
After
bubbling stops, apply a ring of Loctite around stud at top of hole, then back
stud to required height.
Loctite will set in 10 min. to 2 hrs.
Temperature
and humidity affect drying time.
( 2 ) P l a s t i c g a s k e t.
Plastic gasket is used as a seal on large close
fitting metal parts.
Mating surfaces must be clean and degreased. Spread an
even coat (0.061 cubic inch per 40 square inches) on
one
o f
the mating
s u r f a c e s.
Assemble and tighten bolts.
P l a s t i c g a s k e t w i l l d r y i n a p p r o x i-
mately 12-24 hours. Temperature and humidity affect drying time.
( 3 ) U n f i l l e d p i p e s e a l a n t .
Pipe sealant MIL-S-22473D, Product CW seals
against moderate pressures instantly and working pressures when completely dry.
Before application, clean threads to remove oil, grease and metal chips. Fill
the second and third threads completely for 360 degrees.
F o r s y s t e m c l e a n l i-
ness, do not fill leading thread.
Pipe sealant will dry in 6-24 hours at room
temperature. Adjustments for elbows, gages and valves can be made up to 24
hours after application without affecting seal.
2-8
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