Fastener Strength Identification

Metric nuts and bolts are divided into metric fastener strength property classes. The most common metric strength property classes are 9.8 and 10.9. Class identification is embossed on the head of each bolt.
Some metric nuts are marked with single digit strength numbers on the nut face.
Replace a metric fastener with a fastener of equal or greater strength. The strength identification number on a replacement fastener should be the same as, or higher than, the strength identification number on the original fastener.
Replace torque-to-yield fasteners with identical fasteners using Isuzu part numbers.
The metric fasteners used on Isuzu products are designed to international standards. Some non-domestic nut and bolt suppliers may not observe these standards. Non-domestic fasteners may not meet Isuzu requirements for the following reasons:
- Non-domestic fasteners may not display the numbered head marking system.
- Non-domestic fasteners may be weaker than domestic fasteners.
- Non-domestic fasteners may have a different thread pitch.