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What is a fastener?
• A device to locate or hold parts
How do you remove a stuck fastener?
• PLS WD-40 Penetrating Oil
• Apply to threads and shock or vibrate the fastener to encourage the oil to penetrate
• Allow time for oil to work into threads
How do you remove a stuck fastener?
• Use a six point wrench or socket
• Try to tighten slightly, then loosen
• An impact can help shock the fastener loose
• A strong impact will often break off the bolt
How do you remove a stuck fastener?
• Heat can help loosen a fastener
• Too much heat can damage the fastener
• Too much heat can weaken the surrounding metal
When do you use a new fastener?
• Damaged in any way
• Corroded
• Stretched
• Torque to yield bolt
What is a torque to Yield Bolt?
• Most commonly used for head bolts
What replacement fastener should you use?
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
Bolt Length and Diameter
What replacement fastener should you use?
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
What replacement fastener should you use?
• Same Length
• Same Diameter
• Same Thread Pitch
• Same Plating or Material
• Same hardness or GRADE
• Same weight
When do fasteners have to be the same weight?
• Any time the nut or bolt is on a rotating part
• Cooling fans
• Drive pulleys
• Flywheel or clutch or torque converter
• Lug nuts Drive shafts
How do fasteners lock in place?
• Proper torque• Lock washers• Cotter pins• Locking tabs• Self locking nuts• Thread locking compounds
– Red LocTite© Blue LocTite©
USE the BLUE unless specified. Red will not come off!
Do not re-use
• Nylon locking nuts
• Cotter pins
• Nuts in critical locations such as connecting rod nuts
What do you put on the threads?
• Anti-seize compound
• Lubrication
• Lock-tight
• Red? Blue?
• BLUE
• All the above require clean threads
How can you clean, repair threads?
• Thread chasers
• Tap
• Die
• Thread file
Tap
• Cuts internal threads in a hole or nut
• Extremely brittle
• Work back and forth using a tap handle
Die
• Cuts external threads on a rod or bolt
• Will easily cross thread and ruin a bolt
• Thread file can help straighten damaged threads on a bolt
What is torque?
• Torque is a twisting force
• Torque is used to make sure the bolt has the proper clamping force
• Too much force weakens the bolt
• Too little force allows parts to work loose
What is torque?
Ft Lbs vs Inch Lbs
• 12 inch lbs = 1 ft lbs
• 120 inch lbs – 10 ft lbs
How to insure clamping force is correct
#1 Look up specific torque value #2 Insure fasteners are the proper grade, length & finish #3 Clean all thread surfaces #4 Use the proper washer and only if specified #5 Install proper length bolt in hole. #6 Run bolts through to feel for rough or tight threads #7 Lubricate bolts consistently #8 Use a torque wrench that is appropriate
(not on the end of the scale)
Beam Type (Deflecting Beam)
Dial type Dial Indicator
run back to lowest setting between uses
Calibration of Torque Wrench
• Do not use to break loose bolts
• Do torque past capacity of wrench
• Unscrew micrometer (click type) to lowest setting between uses
• Have calibration checked periodically
What is torque to yield?
• Tighten to a specific torque
• Continue to turn the fastener just enough to cause it to begin to stretch
• Typically specified in degrees of rotation
Be careful when using extensions indicated to true torque value when using an extension wrench.
D = (A x T) ÷ (A + B) D = indicated Dial reading on torque wrench A = Length of torque wrench B = length of extension T = torque specified by manufacturer
