Thrush Aircraft S2R-R1340 Maintenance Manual page 86

THRUSH AIRCRAFT, INC – MODEL S2R-R1340
halves around the piston flange. Fit
the packing washer into its position
in the inside groove of the front cone.
Insure the packing
properly seated against the piston
and in the front cone groove.
* NOTE *
If the piston does not turn
freely onto the shaft, make
sure the blades are not set at
different angles, causing the
cylinder and piston to be
cocked out
Check the front cone packing
washer to insure that it is
properly seated.
K. Slide the piston and front cone
assembly into the spider until it
contacts the shaft threads. Carefully
align the piston and shaft threads
and screw the piston onto the shaft.
In no case should force be used to
tighten the piston if there is any
indication of binding or if the threads
are not properly engaged.
L. Torque the piston to 180 foot-pounds
using installation wrench and a four
foot bar. Strike the bar once close to
the wrench with a 2 1/2 pound
hammer while applying 180 foot-
pounds of torque.
M. Place the front cone spacer into the
spider and against the front cone.
Compress the hub snap ring and
install it into the groove in the spider.
Position the piston lock ring in the
top of the spider around the octagon
portion of the piston so that the two
cotter pin holes in the outboard end
of the spider align with two of the
eight cotter pin holes in the lock ring.
Safety the lock ring to the spider with
a cotter pin in each of the two sets of
4-16
AIRCRAFT MAINTENANCE MANUAL
washer is
of alignment.
aligned holes.
should be installed with the heads
toward the piston.
N. Using the blade turning device, turn
the blade to the full high pitch
position. Install the Little Giant seal
on the piston with the chamfered end
facing toward the spider, and seat it
on the piston shoulder. If not using
the Little Giant seal, install the
inboard piston gasket on the piston
with the chamfered
toward the spider, and seat it on the
piston shoulder. Place the outboard
piston gasket on the piston and
against the inboard gasket with the
sealing lips facing away from the
spline.
*NOTE*
The outboard gasket acts as
an oil seal
identified by the single 45
degree chamfer on the edge
of the larger inner diameter.
O. Install the cylinder head gasket in its
seat in the end of the cylinder using
grease, if necessary, to hold it in
place. Install the gasket with the
split face against the cylinder seat.
P. Screw the cylinder head into the
cylinder and tighten it firmly with the
installation wrench and a 1 1/2 to 2
foot bar. Line up one of the locking
holes in the cylinder head lock ring
and snap it into position in the
groove in the cylinder head.
Q. Upon completion of the installation,
all visible cotter pins and lock rings
should be checked for security.
The cotter pins
end facing
and can be
Effective: 01/01/2008