Operation and maintenance manual
Section 300-0080
1
SM 1238 2-98
WARNING
Some fasteners are important attaching parts
which could affect the performance of vital
components and systems, and/or, could result
in major repair expense. Fasteners should be
replaced with parts of the same part number,
or with equivalent parts, if replacement
becomes necessary. Do not use replacement
parts of lesser quality or substitute design. The
torque values shown in the following tables
should be used in all cases, unless otherwise
specified elsewhere in this manual, in order to
avoid possible personal injury or property
damage.
The following torque specification tables are based on
GM Standard Materials for bolts, nuts, studs and self-
locking fasteners based on SAE bolt steel
classifications, or, prevailing torque specifications for
self-locking fasteners.
To prevent the threaded bolts and nuts used on this
equipment from being overstressed during assembly,
MISCELLANEOUS - Standard Bolt and Nut Torque Specifications
and to establish a uniform value to which these
fasteners can be safely tightened, the following torque
tables have been compiled.
The torque values listed in the tables have been
established over a period of years and cover all
conditions of assembly. The maximum torque values
for standard bolts and nuts are based on 75% of the
specified minimum proof strength of the bolt steel in
order to provide a safety factor to compensate for the
variation in the accuracy of torque wrenches, skill of
the assembler, and variance in fractional conditions.
All torque values are for lubricated threads. The
term 'lubricated' includes the application of thread
lubricants, cadmium plating or the use of hardened
washers.
To provide a quick method for determining the GM
material classification of a particular standard bolt or
nut, compare the bolt head markings to those in the
appropriate tables, then locate the maximum torque
value for that bolt size in the column under that
marking.