PREVOST X3-45 Multiplex, Maintenance Manual

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Section 00: GENERAL INFORMATION
PA1562
9
5. FASTENER STRENGTH IDENTIFICATION
Most commonly used metric fastener strength
property classes are 9.8 and 10.9 with the class
identification embossed on the head of each
bolt. Customary (inch) strength classes range
from grade 2 to 8 with radial line identification
embossed on each bolt head actual grade (i.e.,
a grade 7 bolt will have 5 embossed radial lines
on the bolt head). Some metric nuts will be
marked with single digit strength identification
numbers on the nut face. Fig. 14 shows the
different strength markings. When replacing
metric fasteners, be careful to use fasteners of
the same or greater strength than the original
fasteners (the same number marking or higher).
It is also important to select replacement
fasteners of the correct size. Correct
replacement fasteners are available through the
parts division. Some metric fasteners available
in after-market parts sources were designed to
metric standards of countries other than the
United States and may be of a lower strength,
may not have the numbered head marking
system, and may be of a different thread pitch.
FIGURE 13 : THREAD NOTATION
00002
FIGURE 14: BOLT STRENGTH MARKINGS
00003
The metric fasteners used on the coach are
designed to new standards and may not yet be
manufactured by some non-domestic fastener
suppliers. In general, except for special
applications, the common sizes and pitches are: M 8 X 1.25;
M 10 X 1.5;
M 12 X 1.75;
M 14 X 2;