Vehicle Fasteners Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the purpose of tightening fasteners in a crisscross pattern?

To make it easier to remove the fasteners later

To prevent the fasteners from stripping

To achieve a uniform distribution of torque (correct)

To ensure the fasteners rust less

Which type of nut is specifically designed to prevent loosening by creating friction when threaded onto a bolt?

Wing nut

Self-locking nut (correct)

Jam nut

Castellated nut

Why should care be taken when using an air wrench on fasteners?

They might accidentally loosen rather than tighten a fastener

Air wrenches lower the required torque setting

The speed can cause corrosion to the fastener

They can cause bolts to stretch or break due to high speed (correct)

What is the function of a jam nut in a fastener assembly?

To hold larger nuts in place by being tightened against them Signup and view all the answers

Which type of nut has an odd-shaped head and is known for being tightened onto a bolt?

Castle nut Signup and view all the answers

What is the main purpose of a washer when used with a bolt?

To prevent damage to the surface of parts Signup and view all the answers

Which type of screw is specifically designed to hold parts onto shafts?

Set screws Signup and view all the answers

What is a key advantage of using Helicoil for thread repair?

Repairs threads without altering the original size Signup and view all the answers

What is the primary role of split lock washers?

To provide a spring action that prevents loosening Signup and view all the answers

Which type of fastener prevents gears from turning on their shafts?

Taper pins Signup and view all the answers

Which type of washer is known for its ability to provide better holding power on thin materials?

Body or fender washers Signup and view all the answers

Machine screws are characterized by what key feature?

They are threaded along their full length Signup and view all the answers

What is a distinguishing feature of snap rings in mechanical assemblies?

They hold parts onto shafts Signup and view all the answers

Which statement regarding bolt grades is accurate?

Higher numbers on metric bolts denote increased hardness and strength. Signup and view all the answers

What is the purpose of a torque wrench?

To apply a precise amount of turning force when tightening. Signup and view all the answers

Over-tightening a bolt can result in which of the following outcomes?

The bolt may stretch or break. Signup and view all the answers

Why is it important to follow a crisscross pattern when tightening several bolts?

To ensure that parts are clamped down evenly and to prevent warpage. Signup and view all the answers

Upon which factor does the torque specification primarily depend?

The size and grade of the bolt or nut. Signup and view all the answers

Study Notes

Fasteners

Fasteners are bolts, nuts, screws, clips, and adhesives that hold vehicles together
Each fastener is designed for a specific application
Always replace a fastener with the same type as the original equipment manufacturer (OEM) part
Need to be able to identify and use fasteners properly

Objectives

Identify different fasteners used on vehicles
Properly remove and install bolts and nuts
Explain when specific fasteners are used in vehicle construction
Explain bolt and nut torque values
Summarize the use of chemical fasteners
Identify hose clamps

Bolts

Bolts have a head on one end and threads on the other
Cap screws are high-strength bolts
Bolts are named for the body part they hold (e.g., fender bolt) or by shape and head drive
Bolt heads are used for tightening the bolt
Socket wrenches fit over the bolt head
Improper wrench/socket size can strip or round off the bolt
This can damage tools or cause injury

Bolt Measurements

Bolt dimensions (head, grade marking, length, thread pitch, diameter) are needed for work
Metric and US customary (inch) units are used
Refer to measurements on diagrams for specific details

Bolts (Continued)

Bolt length is measured from the threads to the bottom of the head
Bolt diameter is measured around the outside of the threads
Head size is measured across the flats
Common head sizes are 7/16, 1/2, and 9/16 inches
Common metric sizes are 8mm, 10mm, and 13mm
Thread pitch is a measurement of thread coarseness
Bolts and nuts come in coarse, fine, and metric threads
Bolt threads are measured with a thread pitch gauge
Do not mix thread types - it damages the part

Bolts (Continued 2)

Bolts and nuts have right-hand and left-hand threads
Right-hand threads tighten clockwise
Left-hand threads tighten counterclockwise
Left-hand threads have notches or an "L" stamped on them

Bolt Strengths or Grades

Bolt strength is the tightening force needed
Bolts are made from different materials with varying hardness
Bolt grade markings (lines or numbers) on the head indicate strength and hardness
Metric bolts use a property class indicator on the head to indicate hardness
More lines on markings represent more strength
Numerical marking (higher number) indicates more strength in metric bolts

Bolt Strengths or Grades (Continued)

Bolt strength is indicated by lines (more lines mean stronger) in some systems and numeric values (higher numbers mean stronger) in others
Tensile strength is the amount of pressure a bolt can withstand before breaking when pulled apart
Harder bolts have greater tensile strength

Torque

Torque is the turning force when tightening a fastener
Over-tightening can stretch or break a bolt
Under-tightening allows the bolt or nut to loosen and fall out
Torque specifications are the manufacturer's recommendations for a specific bolt or nut

Torque (Continued)

Torque wrenches measure torque values
General bolt torque charts give general torque values for the size and grade of bolt
Bolt threads should be lubricated for accurate results
Tightening sequence or torque pattern ensures that parts are clamped down evenly (use a crisscross pattern)

Torque (Continued 2)

Tighten fasteners in a crisscross pattern
Tighten fasteners in steps, beginning with half-torque, then 3/4 torque, and then full torque at least twice
Be careful when using air wrenches as they can quickly damage fasteners.

Nuts

Nuts have internal threads and an odd head shape, tightened onto bolts
Castellated or slotted nuts have grooves on top for safety wire or cotter pins
Castellated nuts are used with studs that hold wheel bearings in position.
Self-locking nuts produce friction when threaded onto a bolt; the top can be crimped inward

Nuts (Continued)

Certain locking nuts need to be replaced after removal
Some front wheel drive spindles use self-locking nuts
Jam nuts hold larger nuts in place by tightening against another nut, preventing loosening.

Nuts (Continued 2)

Wing nuts have two arms for hand turning
Used frequently on parts that need to be removed easily
Acorn nuts are closed on one end to keep debris and water out
Body nuts have washers to distribute clamping forces and prevent warpage of the body panel or trim piece

Thread Repair

Collision repair technicians often repair damaged threads
Taps are tools for cutting internal threads in holes
Dies cut threads on the outside of bolts or studs
Special t-handles fit over taps or dies for turning

Thread Repair (Continued)

Hold the repair tool squarely when cutting threads
Lubricating the threads helps prevent wear and tear of the tool
Back the tool out a little after cutting to remove metal shavings and avoid tool damage
Helicoils can be used to repair damaged threads

Washers

Washers prevent damage to surfaces and improve holding power
Flat washers prevent smaller heads from coming through sheet metal/plastic
Wave washers create spring action that keeps parts from rattling/loosening
Body/fender washers have large diameters to have better holding power on thin metal and plastic parts
Copper/brass prevent fluid leakage

Washers (Continued)

Spacer washers adjust parts
Fiber washers prevent vibration/leakage, but cannot be tightened easily
Finishing washers have curved shapes for appearance
Split lock washers prevent loosening by vibration
Shakeproof/teeth lock washers use teeth or bent lugs to hold both the work and nut

Screws

Screws hold nonstructural vehicle parts
Machine screws have threads along their full length
Set screws have an internal drive head for Allan wrenches to hold parts to shafts
Some sheet metal screws/self-tapping screws have pointed/tapered tips
Trim screws have washers attached
Headlight aiming screws may have plastic adapters

Nonthreaded Fasteners

Square keys, Woodruff keys prevent cams/pulleys turning on their shafts
Taper pins locate and position matching parts
Dowel pins position and align parts
Cotter pins prevent loosening of nuts/bolts
Snaprings hold parts to shafts, while pop rivets hold sheet metal together

Hose Clamps

Hose clamps hold radiator and heater hoses in place

Adhesives

Epoxy is a two-part bonding agent that dries hard and is waterproof and heat resistant
Trim adhesive is used to install trim pieces to the body and has a rubber-like consistency, bonding plastics, metals, and rubber to painted surfaces.

Summary

Fasteners (bolts, nuts, screws, clips, adhesives) hold vehicles together
Bolt strength determines the amount of torque needed
Nonthreaded fasteners (keys, snaprings, pins, clips, adhesives) do not use threads

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the various fasteners used in vehicle construction. This quiz will cover the identification, proper use, and torque values of bolts, nuts, and other fasteners. Gain insights into OEM replacement and the application of chemical fasteners in automotive settings.