Chrysler RAM TRUCK 2500 1994 Service Manual page 23

18
INTRODUCTION
STANDARD TORQUE SPECIFICATIONS
BOLT TORQUE
B O L T
6 I A D E S
SIZE Nitt
f f - i b s
N * n
ft-lbs
(in-lbs) (in-lbs)
1/4-20 11 (95)
14 (125)
1/4-28 11 (95) 17 (150)
5/16-18 23
(200) 31 (270)
5/16-24 27 20 34 25
3/8-16 41 30 54 40
3/8-24 48 35
61 45
7/16-14 68 50 88 65
7/16-20 75
55 95 70
1/2-13 102 75 136 100
1/2-20 115 85
149 110
9/16-12 142 105 183
135
9/16-18 156 115 203 150
5/8-11 203 150
264 195
5/8-18 217 160 285 210
3/4-16 237
175 305 225
J89IN-9
THREAD NOTATION—SAE AND METRIC
INCH
5/16-18
METRIC
M 8 X 1.25
THREAD
MAJOR
DIAMETER
IN INCHES
NUMBER
OF
THREADS
PER INCH
THREAD DISTANCE
MAJOR BETWEEN
DIAMETER I N THREADS I N
MILLIMETERS MILLIMETERS
PR606B
• A grade 7 bolt has 5 line marks on top of the bolt
head
• A grade 8 bolt has 6 line marks on top of the bolt
head
The most commonly used metric bolt strength
classes are 9.8 and 12.9. The metric strength class
identification number is imprinted on the head of the
bolt (Fig. 2). The higher the class number, the
SAE CLASSIFICATION
GRADE 5
GRADE 8
MARKINGS F O U N D
O N TOP O F BOLT
HEAD INDICATE
GRADE
120°
60°
GRADE 2 GRADE 5 GRADE 8
(SAE) BOLTS—IDENTIFICATION MARKS CORRESPOND
T O BOLT STRENGTH—INCREASING NUMBERS
REPRESENT INCREASING STRENGTH.
J89IN-11
Fig. 1 SAE Bolt Grade Identification
greater the bolt strength. Some metric nuts are im­
printed with a single-digit strength class on the nut
face.
METRIC BOLTS—IDENTIFICATION CLASS NUMBERS
CORRESPOND T O BOLT STRENGTH— INCREASING NUMBERS
REPRESENT INCREASING STRENGTH. J89IN-10
Fig. 2 Metric Bolt Class Identification
METRIC CONVERSION
Refer to the Metric Conversion chart to convert
torque values listed in metric Newton-meters (N-m).
Also, use the chart to convert between millimeters
(mm) and inches (in.)