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PIPER CHEROKEE WARRIOR SERVICE MANUAL
2-8.
TORQUE REQUIREMENTS: Proper torque application cannot be overemphasized. Under torqued
assemblies can result in premature failure due to fatigue from uneven loads, as well as causing unnecessary
wear of nuts, bolts, and other parts. Over torqued assemblies can be equally harmful by causing failure of a
bolt or nut by over stressing the threaded areas.
The torque values given in Table II-II are derived from oil-free cadmium-plated threads and are rec-
o mmended for all airframe installation procedures where torquing is required, unless otherwise noted in sec-
tions where other values are stipulated. Engine torque values are found in the latest revision of Te x t r o n
Lycoming Special Service Publications No. SSP1776, and propeller torque values are found in Section VIII of
this manual. Table II-IIA lists the torque values for flared fittings of various sizes and material. Important
p r ocedures for torquing assemblies on Piper Aircraft are as follows:
a. Frequently check and/or calibrate the torque wrench.
b. MAKE SURE bolt/screw and nut threads are clean and dry, unless otherwise required. If the
threads are to be lubricated and no torque is specified, reduce recommended nut torque (plus the friction drag
torque) by 50%.
c. Unless otherwise specified the charted torque values should be used. Should a bolt or nut be listed
and not its mating fastener, use the lower torque.
d. When using "self-locking fasteners" and hardware with thread sizes 10 through 7/16 add the speci-
fied friction drag torque to the designated torque. Assume a friction drag torque of zero for non self-locking
fasteners. For other bolt sizes the friction drag torque is determined as follows:
1. Turn nut to "near contact" with the bearing surface (NOT IN CONTACT).
2. Attach a scale type torque wrench and determine the torque required to turn the nut on the bolt
before it contacts the bearing surface. Add this value to the specified torque for the total torque value to be
applied.
e.
When torquing castellated nuts remember the following:
1. Determine maximum torque value (friction + max. torque) and do not exceed when aligning
slot and hole, change washers if necessary.
2. When using castellated nuts on movable joints, tighten nuts only to remove looseness in the
joint before installing cotter pin.
f.
Use the latest information from LYCOMING for torquing power plant parts.
g.
On critical installations the nut should be permanently marked red after torquing and not be
further tightened or disturbed.
When flared fittings are being installed, ascertain that the
male threads are properly lubricated. Torque the fittings in
accordance with Table II-IIA. For more details on torquing,
refer to FAA Manual AC 43-13-1A.
Revised: February 28, 1995
CAUTION
Do not over torque fittings.
NOTE
1B3
Island Enterprises
HANDLING AND SERVICING
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