Cessna T188C - 19-88. Inspection and Replacement of; Butterfly Valve Insert

MODEL
188
& T188
SERIES
SERVICE
MANUAL
f. Temporarily
install
adapters
(2) and
(15)
in valve
tween
adapters
(2)
and (15)
and valve
body
(17). These
body (17),
making sure
that packings
(5)
are in place.
dimensions
are equal
to shim (4)
size required
to
DO
NOT INSTALL
BOLTS
at this
time.
properly
assembly
the
valve.
g.
Set valve
upright
on
one adapter,
and place
a
10-lb weight
on top
to compress
the packing.
NOTE
h. Using
a
thickness
gage,
measure
clearance
between
adapters (2)
and (15) and
valve body (17).
Shims (4) are
available in thicknesses
of
These
dimensions
are equal
to shim
(4) size
required
0.005-inch
and 0.014-inch.
Use combin-
to properly
assemble
the valve.
ations
of shims
to most
nearly
meet the
dimensions
measured
for each
gap.
NOTE
i. Remove weight
and adapters
(2 and 15),
and in-
Shims (4) are available inthicknesses
of stall
bolts (1) and washers. Tighten
bolts to normal
0.005-inch
and 0.014-inch. Use
combina- torque
value. Refer to the chart in Section
1 of this
tions of
shims to most nearly
meet the
manual for proper
torque.
dimensions measured for each gap. j. Attach hopper adapter (7) to aircraft hopper,
after lubricating
fitting with
MIL-G-81322A
general
i. Remove weight
and adapters (2
and 15), and
purpose grease.
install bolts (1) and washers.
Tighten bolts to nor-
k. Connect coupling and hose to
respective adapters.
mal torque value. Refer to the chart in Section 1 Check system after curing time of sealant has lapsed.
of
this manual
for proper
torque.
J. Attach
hopper adapter
(7) to aircraft
hopper,
19-88.
INSPECTION
AND REPLACEMENT
OF
after lubricating fitting with
MIL-G-81322A, general
BUTTERFLY VALVE INSERT.
(See figure
purpose
grease.
19-29.)
k. Connect coupling
and hose
to respective
adapters.
Check system after curing time of sealant has lapsed. NOTE
19-87. BUTTERFLY SPRAY VALVE SEAL RE- The following procedures will comply with
PLACEMENT. (See
figure 19-29.)
Single-Engine
Service Letter SE78-59.
NOTE a. Remove bolts and washers from coupler adapter
(2)
and hose
adapter
(15).
The following
procedures
will comply
with
b. Remove
coupler
adapter (2),
O-ring
packings
(3)
Single-Engine
Service
Letter SE78-31.
and (5) and
shims
(4).
c. Remove hose
adapter (15),
O-ring packings
(3)
a. Remove
bolts and washers
from coupler adapter
and (5) and shims
(4).
(2) and hose adapter (15).
b. Remove coupler
adapter (2), O-ring packing
(3)
CAUTIO
and (5), and shims (4).
c. Remove hose adapter (15),
O-ring packings (3)
Do not intermix total shim
thickness from
and
(5), and shims (4).
end-to-end.
CAUTION NOTE
Do not intermix total shim thickness from If Single-Engine Service Letter SE78-31 has
end-to-end.
been complied
with, seals (13) have been
replaced. If the Service Letter has not been
d. Remove seal-attaching screws (14) and nuts, complied with follow procedures outlined in
existing
seal (13), and retainer
(12). Discard (13)
Steps "d" and "e" of paragraph
19-86.
when removed.
e. Install new
butterfly seal (13) in reverse
order d. Remove cover
(9), packings, butterfly valve
of procedures outlined in step "d", coating the screw assembly and insert (6).
threads
with Loctite Sealant (Part
Number 59231. ) e. Squeeze
insert (6). If it can be readily
deformed,
To ensure proper sealing,
close butterfly to where
it is a standard grade polyethylene,
and must be re-
seal (13) first contacts insert (6); tighten screws (14). placed. The high-density polyethylene is extremely
rigid, and cannot
be deformed.
CAUTION. f. If insert (6) is found to be of the proper material
or if a new one
is installed,
inspect the insert
land
Tighten screws
1/4 to 1/2 turn after seating
(20)-to-shaft seal
and hole condition as follows:
to prevent deforming
of seal.
1. Inspect shaft
holes in insert (6) for nicks and
size. The hole should be 0.623 * 0.000, -. 003-inch.
f. Temporarily
install adapters (2) and
(15) in valve This provides
a 0.002-inch to 0.005-inch interference
body (17), making
sure that packings (5) are in
place. fit on the butterfly shaft
(21). Oversize holes or nicks
DO NOT
INSTALL BOLTS at this
time.
can result in valve leakage.
g. Set valve up
on one end and
apply a 10-lb
weight
2. Inspect and
remove any burrs
from butterfly
on
top to compress packing.
shaft
(21).
h. Using a thickness gage,
measure clearance be-
3. Carefully slide shaft (21)
through insert (6).
19-62