Chevrolet Cruze Repair Manual: Metric Fasteners
This vehicle provides fastener dimensions using the metric system. Most metric fasteners are approximate in diameter to equivalent English fasteners. Make replacements using fasteners of the same nominal diameter, thread pitch, and strength.
A number marking identifies the OE metric fasteners except cross-recess head screws. The number also indicates the strength of the fastener material. A Posidrive® or Type 1A cross-recess identifies a metric cross-recess screw. For best results, use a Type 1A cross-recess screwdriver, or equivalent, in Posidrive® recess head screws.
GM Engineering Standards and North American Industries have adopted a portion of the ISO-defined standard metric fastener sizes. The purpose was to reduce the number of fastener sizes used while retaining the best thread qualities in each thread size. For example, the metric M6.0 X 1 screw, with nearly the same diameter and 25.4 threads per inch replaced the English 1/4-20 and 1/4-28 screws. The thread pitch is midway between the English coarse and fine thread pitches.
Fastener Strength Identification
- English Bolt, Grade 2 (Strength Class)
- English Bolt, Grade 5 (Strength Class)
- English Bolt, Grade 7 (Strength Class)
- English Bolt, Grade 8 (Strength Class)
- Metric Nut, Strength Class 9
- Metric Bolts, Strength Class Increases as Numbers Increase
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 in order to identify the strength class. The number of lines on the head of the bolt is 2 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 are designed to metric standards of countries other than the United States, and may exhibit the following:
- Lower strength
- No numbered head marking system
- Wrong thread pitch
The metric fasteners on GM products are designed to new, international standards. The following are the common sizes and pitches, except for special applications:
- M6.0 X 1
- M8 X 1.25
- M10 X 1.5
- M12 X 1.75
- M14 X 2.00
- M16 X 2.00
Fasteners
Table 1: Metric Prevailing Torque Fastener Minimum Torque Development
Table 2: English Prevailing Torque Fastener Minimum Torque Development ...
Prevailing Torque Fasteners
Prevailing torque fasteners create a thread interface between the fastener
and the fastener counterpart in order to prevent the fastener
from loosening.
All Metal Prevailing Torque Fasteners
Thes ...
Other materials:
If a Tire Goes Flat
It is unusual for a tire to blowout while driving, especially if the tires are
maintained properly. If air goes out of a tire, it is much more likely to leak out
slowly. But if there ever is a blowout, here are a few tips about what to expect
and what to do: If a front tire fails, the flat tir ...
Brakes
This vehicle has front disc brakes and could have rear drum brakes or rear disc
brakes.
Disc brake pads have built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads are needed.
The sound can come and go or be heard all the time the vehicle is m ...
Driving for Better Fuel Economy
Driving habits can affect fuel mileage. Here are some driving tips to get the
best fuel economy possible.
• Avoid fast starts and accelerate smoothly.
• Brake gradually and avoid abrupt stops.
• Avoid idling the engine for long periods of time.
• When road and weather conditions ar ...
