Chrysler Concorde 1993 Service Manual page 803

4 INTRODUCTION
METRIC THREAD AND GRADE IDENTIFICATION
Metric and SAE thread notations differ slightly.
The difference is illustrated in Figure 3.
Fig. 3 Thread Notation (Metric and SAE)
Common metric fastener strength classes are 9.8
and 12.9 with the class identification embossed on
the head of each bolt (Fig. 4). Some metric nuts will
be marked with a single digit strength number on
the nut face.
Fig. 4 Metric Bolt Identification
SAE strength classes range from grade 2 to 8 with
line identification embossed on each bolt head. Mark-
ings corresponding to two lines less than the actual
grade (Fig. 5). For Example: Grade 7 bolt will have 5
embossed lines on the bolt head.
METRIC SYSTEM
Figure art, specifications, and tightening references
in this Service Manual are identified in the metric
system and in the SAE system.
During any maintenance or repair procedures, it is
important to salvage metric fasteners (nuts, bolts,
etc.) for reassembly. If the fastener is not salvage-
able, a fastener of equivalent specification should be
used.
WARNING: USE OF AN INCORRECT FASTENER
MAY RESULT IN COMPONENT DAMAGE OR PER-
SONAL INJURY.
The metric system is based on quantities of one,
ten, one hundred, one thousand, and one million
(Fig. 6).
Fig. 5 SAE Bolt Identification
Fig. 6 Metric Prefixes
INTERNATIONAL SYMBOLS
Some International Symbols are used to identify
controls and displays in this vehicle. These symbols
are applicable to those controls which are displayed
on the instrument panel or in the immediate vicinity
of the driver.