APPENDIX B – TORQUES 447
Using a Torque Wrench Extension
Occasionally the need will arise to use an extension,
crowfoot, or other type of adapter with your torque
wrench to torque a bolt or line fitting. Sometimes an
extension or adapter is necessary to reach a bolt in a
hard to reach location. Adding adapters or extensions
will alter the actual clamping force at the fastener. By
using the following formula you can determine what
the torque wrench setting should be to achieve the
known standard or special torque value.
Figure 656 Torque wrench extension
• F – Force applied by service technician
• L – Length through which force is applied to
fastener
•L
E
– Length of extension
•L
W
– Length of torque wrench
•T
E
– Torque applied at fastener
•T
W
– Torque applied at end of torque wrench
•T
S
– Torque wrench setting
T
S
=T
E
(L
W
/(L
W
+L
E
)
Example:
A component has a known torque value of 88 N·m (65
lbf·ft) and an extension is required to reach it. What
will the torque wrench setting have to be in order to
compensate for the additional extension?
• Torque wrench = 12 inches
• Extension = 6 inches
T
S
=65lbf·ft(12in/(12in+6in)
T
S
= 65 lbf·ft (12 in / 18 in)
T
S
= 65 lbf·ft (0.666)
T
S
= 43.3 lbf·ft or 58.9 N·m
EGES-265-2
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© 2009 Navistar, Inc.
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