Cessna 1969-1976 172 Series Service Manual page 119

PROBABLE CAUSE
TROUBLE
FLAPS FAIL TO EXTEND.
Disconnected or defective
DOWN limit switch.
7- 5. FLAP MOTOR AND TRANSMISSION ASSEM-
BLY.
REMEDY
Check continuity of switch.
Connect or replace switch.
7-6. REMOVAL AND INSTALLATION.
a.
THRU AIRCRAFT SERIALS 17259904 AND F172-
00804 WHEN NOT MODIFIED IN ACCORDANCE WITH
SK150-37 AND WHEN NOT MODIFIED IN ACCOR-
DANCE WITH FIGURE 7-2, SHEET 3. (Refer to
figure 7-2, sheet 1.)
1. Run flaps to full DOWN position.
2. Disconnect battery cables at the battery and
insulate cable terminals
as a
safety precaution.
3. Remove a c c e s s plates adjacent to drive pul-
ley and motor assembly on right wing.
l
*
NOTE
Remove motor (I), transmission (4), hinge
assembly (2) and actuating tube (6) from
a i r c r a f t
as a unit
on aircraft equipped with
standard fuel tanks. On a i r c r a f t equipped
with long range tanks, detach motor and
transmission assembly from hinge assem-
bly (2) p r i o r
to removal by removing bolt
(5).
4. Remove bolt (18) securing actuating tube (6)
5. Screw actuating tube (6) IN toward transmis-
6. Remove bolt (3) securing flap motor hinge
to drive pulley (9).
sion (4) by hand to
its
shortest length.
(2) to wing,
or
if long range fuel tanks
are
installed,
remove bolt (5) securing transmission to hinge assem-
bly. Retain b r a s s washer between hinge and wing
structure f o r use on reinstallation.
7. Disconnect motor electrical wiring (21) at
quick- disconnects.
8. Using care, work assembly from wing through
a c c e s s opening.
9. Reverse the preceding steps f o r reinstallation.
If the hinge assembly
(2) w a s removed from the trans-
mission (4) for any reason, ensure the short end of
hinge is reinstalled toward the top.
10. Complete a n operational check
as
outlined in
paragraph 7-3 and re-rig system in accordance with
paragraph 7- 19.
b. THRU AIRCRAFT SERIALS 17259904 AND F172-
00804 WHEN MODIFIED IN ACCORDANCE WITH SK-
150-37 AND WHEN NOT MODIFIED IN ACCORDANCE
WITH FIGURE 7-2, SHEET 3. (Refer to figure 7-2,
sheet 2. )
"a.
It
1. Complete steps 1, 3 and 4 of subparagraph
I
2. Run flap motor to place actuating tube (4) IN
3. Complete steps 2, 6, 7, 8, 9 and 10 of sub-
to its shortest length.
paragraph
"a.
"
59905, F17200805 AND ALL AIRCRAFT MODIFIED
(Refer to figure 7-2, sheets 2 and 3.)
I
C.
BEGINNING WITH AIRCRAFT SERIALS 172-
IN ACCORDANCE WITH FIGURE 7-2, SHEET 3.
1. Complete steps 1 thru 7 of subparagraph "a.
'I
2. Disconnect electrical wiring
at
limit switches
(29 and 32). Tag w i r e s for reference on reinstalla-
tion.
3. Complete steps 8, 9 and 10 of subparagraph
II.. I l
a .
7-7. REPAIR. Repair consists of replacement of
motor, transmission, coupling, actuating tube and
associated hardware. Bearings in hinge assembly
may also be replaced. Lubricate
as
outlined in
Section 2.
7-8. DRIVE PULLEYS. (Refer to figure 7-2.)
7-9. REMOVAL AND INSTALLATION.
a.
Remove a c c e s s plates adjacent to drive pulley
b. Unzip
o r
remove headliner
as
necessary f o r
(9) i n right wing.
a c c e s s to turnbuckles (index 6, figure 7- l), remove
safety w i r e and loosen turnbuckles.
c. Remove bolt (15) securing flap push-pull rod
(10) to drive pulley (9) and lower RIGHT flap gently.
d. Remove bolt (18) securing actuating tube (6) to
drive pulley (9) and lower LEFT flap gently. Re-
tain bushing.
e. Remove cable locks (8) securing control cables
to drive pulley (9). Tag cables for reference on re-
installation.
f . Remove pin (17) attaching transmitter rod (14)
to a r m (16).
g. Remove bolt (7) attaching drive pulley (9) to
wing structure.
h. Using care, remove drive pulley through access
opening, being careful not to drop bushing. Retain
b r a s s washer between drive pulley and wing structure
for use on reinstallation. Tape open ends of drive
pulley a f t e r removal to protect bearings.
i. To remove left wing drive pulley, use this same
procedure omitting steps "d" and "f.
I f
j .
Reverse the preceding steps for reinstallation.
Rig system i n accordance with paragraph ' 7 -19,
safety turnbuckles and reinstall all i t e m s removed
for access.
Change 1 7-3