Cessna 188 Series Service Manual page 148

MODEL 188 & T188 SERIES SERVICE MANUAL
NOTE f.
With bearing (6) flush with end of housing (12),
carefully drill bearing so the drill will emerge
Relative linear movement between internal
from the hole on the opposite side of housing (12).
threaded screw (9) and bearing (14) should
DO NOT ENLARGE HOLES IN HOUSING.
be 0.004 to 0.010 inch at room temperature. g.
Press new groov pins (10) into the pin holes.
h. Insert collar (7), new O-ring (13) and bearing
e.
Examine threaded rod end (15) and screw (9) for (14) into opposite end of housing (12).
damaged threads or dirt particles that may impair i.
Complete steps "f" and "g" for bearing (14).
smooth operation.
j. If a new bearing (16) is required, a new bearing
f.
Check sprocket (5) for broken, chipped and/or
may be pressed into the boss. Be sure force bears
worn teeth.
against the outer race of bearing.
g. Check bearing (16) for smoothness of operation. k.
Screw the threaded rod end (15) into screw (9).
h. DO NOT attempt to repair damaged or worn
1.
Install retaining rings (11), if they were re-
parts of the actuator assembly. Discard all defective
moved.
items and Install new parts during reassembly.
m. Test actuator assembly by rotating sprocket (5)
with fingers while holding threaded rod end (15).
9-10. REASSEMBLY.
(See figure 9-4.)
The threaded rod end should travel in and out smooth-
a.
Always discard the following items and install ly, with no indication of binding.
new parts during reassembly.
n.
Reinstall actuator assembly in accordance with
1. Groove Pins (8 and 10) paragraph 9-7.
2. O-Ring (13)
3. Nuts (2).
9-11.
TRIM TAB FREE - PLAY INSPECTION.
b.
During reassembly, lubricate collars (7)
a. Place elevator and trim tab in neutral position
screw (9) and threaded rod end (15) in accordance
and secure from movement.
with Section 2.
b. Determine maximum amount of allowable free
c.
Slip collar (7) and bearing (6) on screw (9).
play using formula shown in figure 9-2.
d.
Press sprocket (5) into the end of screw (9),
c. Using moderate hand pressure ( up and down),
align groove pin holes and install new groove pin (8).
measure free-play at trailing edge of trim tab.
e.
Insert screw (9), with assembled parts, into
d. If trim tab free-play is less than maximum allow-
housing (12) until bearing (6) is flush with the end of
able, the system is within prescribed limits.
housing.
e. If trim tab free-play is more than maximum
allowable, check the following items for looseness
NOTE
while moving trim tab up and down.
1. Check push-pull tube to trim tab horn assem-
When inserting screw (9) into housing (12),
bly attachment for looseness.
locate the sprocket (5) at the end of housing 2.
Check push-pull tube to actuator assembly
which is farther away from the groove for
threaded rod end attachment for looseness.
retaining ring (11).
3.
Check actuator assembly threaded rod end
for looseness in the actuator assembly.
* New bearings (6 and 14) are not pre-drilled
f.
If looseness is apparent while checking steps
and must be drilled on assembly. The groove
e-l and e-2, repair by installing new parts.
pins (10) are 1/16 inch in diameter and require g.
If looseness is apparent while checking step
a 1/16 (0. 0625) inch drill e-3, refer to paragraph 9-6 through 9-10.
HINGE POINT
HINGE POINT -r
TRAILING EDGE
TRAILING EDGE Detail
E
TRIM TAB
- -
Detail
A
1. Measure chord length at extreme inboard end of
E FREE-PLAY UP
trim tab as shown in detail A.
2.
Mulitiply chord length by 0.025 to obtain maximum
* NEUTRAL POSITION
allowable free-play.
o
FREE-PLAY DOWN
3. Measure free-play at same point on trim tab that
A* TOTAL FREE-PLAY
chord length was measured.
4.
Total free-play must not exceed maximum allow-
able. Refer to detail B.
Figure 9-2. Trim Tab Free - Play Inspection
9-5