GMC chevrolet camaro 2000 Service Manual page 30

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General Information
The most commonly used metric fastener strength
property classes are 9.8 and 10.9. The class
identification is embossed on the.head of each bolt.
The English (inch) strength classes range from grade 2
to grade 8. Radial lines are embossed on the head
of each bolt to identify the strength class. The number
of
lines on the head of the Qolt is two lines less
than the actual grade. For example, a grade 8 bolt will
have 6 radial lines on the. bolt head. Some metric
nuts are marked with a single-digit strength
identification number on the nut face.
The correct fasteners are available through GM SPO.
Many metric fasteners available in the aftermarket
parts channels were designed to meet the metric
standards of countries other than the United States,
and may exhibit the following defects: ·
e
Reduced strength
c
No numbered head marking system
e
Wrong thread pitch
The metric fasteners on GM products are designed
to
new, international standards. The following are the
most common sizes and pitches, except
for
special
applications:
e
M6.0X i
0
MS X 1.25
®·
MiO X 1.5
o
M12 X i.75
General Information 0-19
Prevailing Torque Fasteners
2
3
4
.5
6
7
8
9
171892
legend
(1) Prevailing Torque Nut, Center Lock Type
(2) Prevailing Torque Nut, Top Lock Type
(3) Prevailing Torque Nut, Nylon Patch Type
(4) Prevailing Torque Nut, Nylon Washer
Insert Type
(5) Prevailing Torque Nut, Nylon Insert Type
(6) Prevailing Torque Bolt, Dry Adhesive
Coating Type
(7) Prevailing Torque Bolt, Thread Profile
Deformed Type
(8) Prevailing Torque Bolt, Nylon Strip Type
(9) Prevailing Torque Bolt, Out-of-Round Thread
Area Type
A prevailing torque nut is designed to develop an
interface between the nut and bolt threads. Distortion
of the top of a metal nut or the use of a nylon
patch on the threads in the middle of the hex flat
provides the interface.