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tube,
partially
extend
the
strut
and insert
the
orifice
Federal
Specification
PD-680,
and immerse
parts
in
tube
into
the
barrel.
clean
hydraulic
fluid,
Specification
MIL-H-5606,
prior
to
reassembly.
i. Install
the
orifice
tube
retaining
snap ring with
the
beveled
side down.
c.
If fluid leaks
have been observed
on
top
of the cap
assembly,
check
the
small
"O" ring of
the
valve;
then
j.
Raise
and lower
the
strut
several
times to
remove
look for defects
in
the
valve.
air
and excess
fluid.
d. If
the
leak seems
to
be coming
from
the
junction of
k.
Install
the
air
valve
assembly.
the
air valve
assembly
and
the
barrel
assembly
walls,
check the
large
"O"
ring
gasket
under
the
barrel
end
1. Inflate
the
strut
to
approximately
100 psi.
Coat
the
Plug.
cap and air valve with soap suds and check for air leaks.
e. If fluid is
observed
leaking out
the
bottom of
the
pis-
DISASSEMBL
Y OF MAIN GEAR
SHOCK
STRUT
ton, the
small
"O" ring
near
the
lower
end of
the
re-
(Airplanes
prior
to
Serial
TD-252)
bound
control
assembly
rod
may be defective
or
the
seating
of
the
rod may not be
firm.
Inspect
the
inside
a.
Remove
the
air
valve
cap and depress
the
valve
bottom
of
the
piston
to
see
that the grooved
seating
for
core
to
release
the
air inside
the
strut.
the
rod is clean and
smooth.
WARNING
f. After
pressing
new bushings
(15, 21) in knees,
line
ream
to
0, 5000 inches
plus
or minus
0. 0005 inches.
Do not unscrew
the
air valve assembly
until all
MAIN SHOCK STRUT
WEAR
TOLERANCES
air pressure
has been
released
or it may be
(Airplanes
prior
to
Serial
TD-252)
blown off with considerable
force
and cause
in-
jury
or damage·
The following
are
manufacturing
tolerances
which will
aid
in determining
the
extent
of
wear.
The exact allow-
b. Remove
the
air valve
assembly.
able
deviation
from
these tolerances
must be
determined
c.
Remove
the
snap
ring,
lock,
plug and "O" ring.
by
the
performance
of
the
strut.
d.
Invert
and drain
the
strut.
Pins
(27
and 22) O.
D. (minimum)
0. 4985 in.
e.
Detach
the torque
knees
by removing
the
attaching
Bushings
(15 and 21) bore
(maximum)
0.
5005 in.
hardware.
Chrome
plated
portion
of absorber
f.
Disengage
the
rebound
control
assembly
from
the
assembly
piston
(20) O. D. (minimum)
1.
862
in.
piston
assembly
by
holding
the
pin
assembly
head of
the
rebound
control
assembly
with
a
long
screwdriver
in-
Upper
(9) and lower
(16)
bearings
serted
through the top
of
the
barrel
assembly
and re-
I. D. (maximum)
1. 866
in.
moving
the
retaining
nut.
Bushing
(28)
O.
D. (minimum)
.
433
in.
e.
Pull
the
rebound
control
assembly
out
through the
top
of
the
barreL
Bushing
(28)
L
D. (maximum)
.
315
in.
h.
Slide
the
piston
out
the
bottom
of
the
barrel.
Experience
in
the
field indicates
the
points
of greatest
wear
on
both
the
main
and
nose gear
struts
are
the
up-
i.
Remove
the
snap
ring,
adapter
ring
and scraper
per and lower bearings
in
the
barrel
and
the
piston.
The
from
the
bottom
of
the
barrel.
forces
exerted
on
the
bearings
and
the
piston
during
take-off
and
landing
tend
to
result
in an out-of-round
j.
Remove
the
felt lubricating
pad from
the
lower part
condition.
The
out-of-round condition
of
the
piston
com-
of
the
barrel.
bined with
the
wear
of
the
upper
bearing
in
the
barrel
will
eventually
result
in leakage
of hydraulic
fluid
through
k. Remove
the
"O" ring from
the
groove
in
the
center
the
upper
bearing
and
"O" ring.
The fluid
will seep
brazed
bearing
inside
the
cylinder with a piece of
wire
down
through the
felt lubricating
liner
and out
the
lower
bent
as
shown in Figure
5-2.
bearing.
L
Remove
the
"O" ring
and
plastic
back-up
rings
from
When replacement
of
the
scraper
ring
(17)
and all "O"
the
rebound
control assembly.
rings
and
Teflon
packing
rings
in
the
strut
assembly
fails
to
stop
leaks,
an out-of-round
condition
of
the
INSPECTION
AND
PARTS
REPLACEMENT
bearings
and
piston
is probable.
In such instances
the
strut
assembly
should
be returned
to
the
factory
for
complete
reconditioning.
Field replacement
of
the
lower
a.
Check
the
complete
strut assembly
for
cracks,
weld
bearing
in
the
barrel
is possible;
however,
the
concen-
breaks
and corrosion.
Replace
worn or defective
parts·
tricity tolerance
between
the
upper
and lower
bearings
is critical
and
factory
reconditioning
of
the
barrel
us-
b. Replace
"O"
ring
seals.
Clean
parts
with solvent,
ually
will be more
satisfactory.
5-7
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Table of Contents
Troubleshooting
