Fastener
Fastener
Fastener
•Vice Grips (locking pliers) damage the head of a bolt or nut and make it
MUCH more difficult to remove.
• This provides a very consistent clamping load and helps keep an even
sealing pressure for the head gasket
This is how you identify
torque-to-yield bolts
Torque to Yield bolts require special procedures
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
Bolt Length and Diameter
Thread Pitch is measured with a special
gauge
The correct gauge will match the grooves of
the bolt
This gauge has a the same thread pitch as the
bolt
This gauge has a different thread pitch than
the bolt
Same Pitch
Different Pitch
These gauges can measure the diameter, pitch and
bolt length
What replacement fastener should you use?
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
Always use the same plating or material as
the original fastener
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
Bolt Grade
• Cooling fans
• Drive pulleys
You should replace these with new ones to ensure they do not fail
How do fasteners lock in place?
• Thread locking compounds are often used
• Use the BLUE unless specified. Using Red LocTite© will make a bolt almost
impossible to remove after it the LocTite cures
• Cotter pins
Some lock nuts are distorted at the top to create an interference fit.
These will wear out after being removed and installed several times
Inspect all self locking nuts
• Some lock nuts use a nylon insert that may wear out if they are
removed and installed too often
Inspect all self locking nuts
• Blue LocTite© will help keep nuts and bolts from vibrating loose