Level 3 ApprenticeshipLevel 3 Apprenticeship

InertiaInertia

• DefinitionDefinition: An object at rest tends to remain at rest, and an object in motion tends to continue in motion in a straight line unless acted upon by an outside force..

Inertia ContinuedInertia Continued

• For example, passengers in an accelerating automobile feel the force of the seat against their backs overcoming their inertia so as to increase their velocity. As the car decelerates, the passengers tend to continue in motion and lurch forward. If the car turns a corner, then a package on the car seat will slide across the seat as the inertia of the package causes it to continue moving in a straight line

External force is holding

Internal forces keepmoving

Forces within the vehicle resist movement

External forces continue to move

Rear CollisionRear Collision

Simple CollisionSimple Collision

Structure CollapsesUniformly

Simple CollisionSimple Collision

Pull

Hold

Strength and design of Body structure will dictate the deflection of collision forces acting upon it

DeflectionDeflection

• a change of course after hitting somebody or something, or a changing of an objects course by being hit by it

Deflection of ForcesDeflection of Forces

Frame DesignFrame Design

Deflection From Direction of Deflection From Direction of TravelTravel

Offset frontalOffset frontal

Deflection From Direction of Deflection From Direction of TravelTravel

Side impactSide impact

Another ExampleAnother Example

Three Section PrincipleThree Section Principle

Front Centre RearFront Centre Rear

Frontal Collision ForcesFrontal Collision Forces

Frontal ImpactFrontal Impact

1

Stage 1Stage 1

Stage 2Stage 2

Stage 3Stage 3

4

Stage 4Stage 4

Forces in a Rear CollisionForces in a Rear Collision

Stage 1Stage 1

Stage 2Stage 2

Stage 3Stage 3

Stage 4Stage 4

Side ImpactSide Impact

Side ImpactSide Impact

Side ImpactSide Impact

#2#2

#3#3

Forces Present in a RolloverForces Present in a Rollover

Typical RolloverTypical Rollover

#2#2

#3#3

MeasurementMeasurementReferenceReferenceSourcesSources

MeasurementMeasurementReferenceReferenceSourcesSources

CENTRE LINECENTRE LINE

• IS AN IMAGINARY LINE THAT RUNS LENGTHWISE THROUGH THE VEHICLE AND IS A REFERENCE FOR DETERMINING LATERALALIGNMENT AND MEASUREMENT

LATERAL LATERAL MEASURMENTMEASURMENT

Centre Plane

Centre Line

CL

CENTERLINECENTERLINE IS USED TO REFERENCE WIDTH THROUGHOUT THE VEHICLE. COMPONENTS MAY BE POSITIONED EQUALLYEQUALLY OFF OF CENTRE (SYMMETRICAL)OR UNEQUALLYUNEQUALLY OFF OF CENTRE (ASYMETRICAL)

DATUM • IS AN IMAGINARY LINE WHICH IS USED TO ESTABLISH

THE HEIGHT OF THE VEHICLES COMPONENTS AND IS A REFERENCE FOR DETERMINING

VERTICAL MISALIGNMENT

DATUM PLANE

DATUM PLANEDATUM PLANE

•The reference line for all vertical body dimensions

ZERO PLANESZERO PLANES

CENTREFRONT REAR

From the ‘Zero’ Plane we can establish length measurement

0

0

From the ‘Centre’ Plane we can establish width

The ‘Datum’ Plane establishes Height dimensions

With these dimensions we can reference all known control points

L

W

H

Measuring ToolsMeasuring Tools

Datum Length Vs. Point to Point

TYPES OF MEASURING SYSTEMSTYPES OF MEASURING SYSTEMS

1. UNIVERSAL1. UNIVERSAL -Mechanical -Laser -Sonic

2. DEDICATED BENCH AND FIXTURE MEASURING2. DEDICATED BENCH AND FIXTURE MEASURING -Mechanical-Mechanical -Laser-Laser

SELF CENTERING GAUGE

Strut Tower GaugeStrut Tower Gauge

Cross member Pin

Digital Tram GaugeDigital Tram Gauge

Most Mitchell, Chief, & Hein-Werner specificationscan be measured using a tram gauge set at equallengths. Measurements can be read directly fromthe tram gauge bar scale or by measuring the distance from pointer to pointer

Tram GaugeTram Gauge

Tape MeasureTape Measure

TermsTerms

• perpendicular

1. at right angles: at right angles to a line or plane2. vertical: perfectly vertical

Laser SystemsLaser Systems

- Single target- Mirrored / Beam splitter / 3d- Multi laser 3d- Reflective pulse laser

Basic theory behind Genesis style systems

Multi TargetLaser

Universal System

Fixed Universal systemFixed Universal system

Universal Bench

Dedicated Bench

Laser Measuring

DatalinerDatalinerLaser measuringLaser measuringsystemsystem

Dedicated Bench and Fixture System

Measuring Systems on the Measuring Systems on the InternetInternet

• http://www.car-o-liner.se/us/• http://www.dataliner.se/• http://www.hein-werner.com/• http://www.chiefautomotive.com/• http://www.lasermateusa.com/• http://www.celette.com/

CRITICAL MEASUREMENTCRITICAL MEASUREMENT

REFERS TO ANY DISTANCE FROM ONE POINT TO ANOTHER THAT MUST BE MEASURED ACCURATELY

TO DIAGNOSE STRUCTURAL DAMAGE

THESE AREAS INCLUDE: • TORQUE BOX WIDTH AND LENGTH• FRAME HORN WIDTH AND LENGTH

• BALL JOINT POSITION• SRUT TOWER POSITION

• SUSPENSION MOUNTING POINTS ETC.

WHILE MOST MEASUREMENTS REQUIRE A DIMENSIONSHEET, QUITE OFTEN CHECKING ONE SIDE TO

ANOTHER WILL SUFFICE IF NO DIMENSION EXSISTS

BASIC STRUCTURAL ALIGNMENT

Body Centre MarkingsBody Centre Markings

Picture the Vehicle as a Box

The Box is Divided Into 3 Sections

BY HANGING GAUGES ON THE UNEVEN BODY OF THEVEHICLE ALLOWS US TO LOOK AT THE UNDERBODY

AS A FLAT LEVEL PLANE. THE GAUGES ALSO DIVIDE THE PLANE INTO THREE SECTIONS

Front Centre RearFront Centre Rear

THIS ALLOWS US TO VIEW THE GAUGES TO DETERMINE

IF THE PLANE HAS BEEN DISTORTED BY THE COLLISION

EXAMPLES OF LATERAL AND VERTICAL MISALIGNMENT

INCORRECT DATUM

While level and datum both relate to vertical While level and datum both relate to vertical (up/down) alignment all three sections are still(up/down) alignment all three sections are still

Level or parallel with each otherLevel or parallel with each other

TWISTTWIST

This structure is out of parallel (twist)This structure is out of parallel (twist)this type of damage is not considered athis type of damage is not considered adatum misalignment as the front and datum misalignment as the front and

rear sections are not up or down relativerear sections are not up or down relativeto the centre sectionto the centre section

Incorrect datumIncorrect datum

On the other hand, a vehicles front or rear On the other hand, a vehicles front or rear section can be vertically misaligned (datum)section can be vertically misaligned (datum)and still remain parallel (level) to the centreand still remain parallel (level) to the centre

sectionsection

Datum and Level MisalignmentDatum and Level Misalignment

THREE STEPS FOR GAUGING:

1. DIVIDE THE VEHICLE INTO THREE SECTIONS2. LOCATE ITS CONTROL POINTS3. ESTABLISH A BASE FOR THE GAUGING PROCESS

CONTROL POINTS:CONTROL POINTS:

• A POINT ON WHICH ANY STRUCTURAL ALIGNMENT IS DEPENDENT• POINTS UPON WHICH ALL MEASURING MUST BE TAKEN TO DETECT COLLISION DAMAGE

BASIC CONTROL POINTS

MANUFACTURERS USECONTROL POINTS FORPOSITIONING OF STRUCTUREDURING MANUFACTURE

TECHNICIANS USE THEM AS GUIDES DURING THE REPAIR PROCESS

COMMON REFERENCE AREAS:- HOLES- BOLTS- STUDS- SUSPENSION MOUNTING POINTS- RIVETS

ESTABLISHING A BASE

FIRST ESTABLISH THE CENTRE SECTION

22

33

BY INSTALL GAUGES AT THE EXTREME FRONT ANDREAR OF THE STRUCTURE, WE DIVIDE THE VEHICLE INTO

THREE BASIC SECTIONS FOR GAUGING PURPOSES

• WITH THESE GAUGES INSTALLED, YOU CAN NOW COMPARE THE TWO BASE GAUGES TO EACH OTHER TO CHECK THE

CONDITION OF THE CENTRE SECTION.• YOU CAN THEN SIGHT THE FRONT AND REAR SECTIONS

FROM THE BASE SECTION TO DETERMINE COMPLETEAND OVERALL STRUCTURAL CONDITION

ADDITIONAL CONTROL POINTS

- LOWER SUSPENSION IF IN THE AREA OF IMPACT

- STRUT TOWERS IF UNITIZED

- STEERING ATTACHMENT POINTS

CONTROL AREAS

- MAY REQUIRE REMOVAL OF MECHANICAL COMPONENTS TO FACILITATE MOUNTING

- MAY REQUIRE ADAPTERS TO FACILITATE MOUNTING

USING DATUM

- WHAT IS THE PURPOSE OF DATUM IN TERMS OF COLLISION DAMAGE ANALYSIS AND REPAIR?

- WHEN SHOULD DATUM BE USED?

PURPOSE

- PROPER SHEETMETAL ALIGNMENT- PROPER HEIGHT OF SUSPENSION MOUNTING AREAS

USAGE

- ANYTIME THE BODY STRUCTURE HAS BEEN COMPROMISED AND STRUCTURAL COMPONENTS ARE INVOLVED

...DIFFERENCES. SHEET METAL VS DIMENSION

Setting DatumSetting Datum

• Datum – 1. point of reference: a point, line, or surface

used as a basis for measurement or calculation in mapping, surveying or measuring

– Datum is used for all vertical alignment measurements

– Used to restore and check correct positioning of both sheet metal and major control points

Areas of givenMeasurement reference

Measurement ReferencePoints to Observe

Setting DatumSetting DatumControl Points

Datum Length Vs. Point to Point

WHEN READING GAUGES, USE THE CENTRESECTION AS YOUR BASE REFERENCE POINT

TAKE NOTE OF LOADED ANDTAKE NOTE OF LOADED AND UNLOADED SPECIFICATIONS!UNLOADED SPECIFICATIONS!

OPTIONAL MOUNTING PRACTICESOPTIONAL MOUNTING PRACTICES

The location of thecorrect datum willbe shown in thedimension manual

OVERCOMING OBSTACLES BY REVISING DATUM

Datum Revision SheetDatum Revision Sheet

SWAY: LATERAL MISALIGNMENT OF THE VEHICLE CENTRELINE (FRONT OR REAR)

DAMAGE RELATING TO CENTRELINE

DAMAGE RELATING TO LEVEL

• THE TERM “LEVEL” REFERS TO ALL AREAS OF THE VEHICLE BEING PARALLEL TO ONE ANOTHER

• HAS NOTHING TO DO WITH THE WAY THE VEHICLE SITS

• CAN REFER TO THE FRONT, CENTRE OR REAR SECTIONS BEING OUT OF ALIGNMENT

• SLANG TERMINOLOGY FOR THIS CONDITION WOULD BE “DOWN AT THE COWL” WHEN IN FACT THE VEHICLES LEFT FRONT RAIL IS ACTUALLY “UP”.

• AS THE VEHICLE RESTS ON ITS SUSPENSION, IT WILLAPPEAR TO SAG AT THE LEFT COWL AREA

VERTICAL MISALIGNMENT

HIGH OR LOWRAIL IS THECORRECT TERM

• THIS TERMINOLOGY LEADS YOU TO BELIEVE THAT THE VEHICLE NEEDS JACKING AT THE LEFT FRONT TORQUE BOX

• WHAT IS REQUIRED IS BLOCKING AT THIS AREA, AND A DOWN PULL ON THE LEFT FRONT RAIL

TWISTTWIST

THE EXCEPTION TO THE RULE IS “ TWIST ”.

- TWIST REFERS TO AN OUT OF LEVEL CONDITION INTHE CENTRE SECTION

- TWIST WILL HAVE (2) HIGH AND (2) LOW AREAS PRESENT

- THE HIGH AND LOW AREAS WILL BE DIAGONAL OF EACH OTHER

LEVEL ONLY REFERS TO PARALLEL WITHIN THE VEHICLESSTRUCTURE, AND HAS NOTHING AT ALL TO DO WITH HOW THE VEHICLE SITS IN RELATION TO THE FRAME

MACHINE OR THE FLOOR

LevelLevel

PERSPECTIVE VIEW AND TOP VIEW

TWIST

DAMAGE RELATING TO DATUM

INCORRECT DATUMONLY

DIFFERENCES

DIAMOND

DIAMOND

- THIS CONDITION ARISES WHEN ONE FRAME RAIL ISMISLOCATED FORWARD OR REARWARD OF THE OTHER

- THIS CONDITION IS APPARENT WHEN MEASURING THECENTER SECTION DIAGONALLY (“ X ”)

- NOT GENERALLY DIAGNOSED BY SELF CENTERINGGAUGES

COLLAPSED RAIL

- RAIL LENGTH IS COMPROMISED

- DETECTED BY LENGTH MEASUREMENT USING A TRAMBAR

CHECK LENGTH, WIDTH AND CROSS MEASURMENTS

COLLAPSED CROSSMEMBER

WIDTH MEASURMENTWIDTH MEASURMENT

STRUT TOWER AND LOWER BALL JOINT WIDTH

AFFECTS CAMBER AND SAI

BALL JOINT LENGTH

AFFECTS CASTER

STRUT TOWER AND LOWER BALL JOINT LENGTH

AFFECTS CASTER

READING SELF CENTERING GAUGES

THESE GAUGES SHOW CORRECT FRAME OR BODYALIGNMENT

Out of LevelOut of Level

SagSag

SideswaySidesway

Sequencing for DiagnosisSequencing for Diagnosis

• Twist (centre section only)• Diamond (affects centreline front and rear)

• Level (parallel readings front and rear)

• Mash (length)

• Sidesway (centreline)

• Measurements (taken constantly)

Perfect AlignmentPerfect Alignment

Sway

Out of Level Out of Level

Diamond? Diamond?

POSITION YOURSELF CORRECTLY TO VIEWTHE GAUGES

Incorrect

Correct

CORRECT DISTANCE6’-10’ AWAY

POSITIONING

TOO CLOSE

CORRECT

- THE TECHNICIAN MUST ALWAYS POSITION HIM ORHERSELF IN A CENTRAL LOCATION AS WELL AS BEING

THE CORRECT DISTANCE AWAY

WHEN GAUGING FOR PARALLEL (LEVEL), YOU MUSTSIGHT THE GAUGES WITH BOTH EYES OPEN

WHEN GAUGING FOR CENTRELINE (LATERAL MISALIGNMENT)SIGHT WITH ONE EYE ONLY

ALWAYS USE THE CENTRE (BASE) GAUGESAS YOUR REFERENCE POINT IN DETECTING

ANY MISALIGNMENT

SOMETIMES SIGHTING FROM THE OPPOSITE END

AIDS THE TECHNICIAN WITH A CLEARER VIEW

VIEWING FROM THE OPPOSITE END OF THE VEHICLE

CHECKING THE CENTRE SECTION

IF NO DIMENSIONS ARE AVAILABLE FOR DIAGONALMEASUREMENT, THE FOLLOWING WILL APPLY:

- IN THE CENTRE SECTION, CHECK THE LENGTH ANDWIDTH OF REFERENCE POINTS AVAILABLE

- ONCE VERIFIED EQUAL, SIDE TO SIDE AND END TO END, A CROSS MEASUREMENT CAN BE ACCOMPLISHED

THIS IS AN EXAMPLE OF INCORRECT WIDTHTHAT WOULD CAUSE A PROBLEM WITH A “X”

MEASUREMENT

IT IS POSSIBLE TO USE A STEEL MEASURING TAPETO ACCOMPLISH A CROSS MEASUREMENT,PROVIDING THERE ARE NO OBSTRUCTIONSWHATSOEVER

USE A TRAM BAR WHENEVER POSSIBLE

ON PICKUP TRUCKS THE CENTRE SECTION ISRELATIVELY SMALL

EXTRA PRECAUTIONS SHOULD BE MADE SO AS NOTTO MEASURE OUTSIDE OF THE CENTRE SECTIONOR INACCURATE READINGS WILL OCCUR

CORRECT PROCEDURE

INCORRECT MEASURING

DO NOT USE CAB MOUNTS AS A REFERENCE POINT

DIAMOND FRAME

CENTRELINE MISALIGNMENT RESULTING FROMDIAMOND

TYPICAL

NON-TYPICAL

DIAMOND AND SWAY

THIS SITUATION IS PRECISELY WHY WE CHECKFOR DIAMOND FIRST

- ONCE CHECK FOR DIAMOND IS COMPLETE, INSTALLTHE TWO BASE GAUGES, #2 & #3.- COMPARE THEM FOR PARELLEL TO DETERMINEIF A TWIST CONDITION EXISTS

- IF THE GAUGES ARE NOT PARALLEL, A TWIST EXISTS

CORRECTALIGNMENT

TWISTEDSTRUCTURE

- ALTHOUGH TWIST CAN ONLY EXIST IN THE CENTERSECTION, THE TECHNICIAN CAN ASSUME IT WILLAFFECT THE LEVEL CONDITION OF THE END SECTIONS

REMEMBER, TWIST ONLY EXISTS IN THE CENTRESECTION, ERRORS IN DIAGNOSIS WILL OCCUR

IF THIS THOUGHT PLAN IS NOT FOLLOWED!

DETERMINING DAMAGE IN THE FRONT OR REARSECTIONS

Out of Level

PREDICTABLE AREAS OF DAMAGE

KEY AREAS OF GAUGE PLACEMENT

DO NOT OMIT THIS GAUGEIF FRONTAL IMPACT IS SUSPECT

DO NOT OMIT CROSSMEMBER GAUGE!

This is the correct method

READ # 1B GAUGE TO THE #2 BASE GAUGE,

Correct method ofreading the main cross member to the base gauge

THEN READ THE 1A GAUGE TO THE 1B GAUGE

THIS IS THE CORRECT PROCEDURE

TRUE SWAY: NO OTHER DAMAGE AFFECTS CENTRELINE

NOTICE THE FRONT SECTION IS OUT OF SQUAREAND DAMAGE CAN ONLY BE CORRECTED BY PULLING

LATERALLY

DIAMOND CONDITION WILL AFFECT CENTRELINE ON BOTH ENDS OF THE VEHICLE, HOWEVER THIS IS NOTA SWAY CONDITION SINCE PULLING THE DIAMOND-

WILL CORRECT CENTRELINE. NO CORRECTION FORSWAY WILL BE NECESSARY

RAIL LENGTH / SHORT RAIL• AS ONE SIDE IS SHORTENED BY THE FORCE OF THE COLLISION, IT DISTORTS THE CENTRELINE READINGTOWARD THAT SIDE OF THE VEHICLE.

• AGAIN, THIS IS NOT A TRUE SWAY SINCE PULLINGSTRAIGHT FORWARD TO RESTORE THE RAIL LENGTHWILL CORRECT THE CENTRELINE

OTHER ISSUES THAT CAN CAUSE CENTRELINEMISALIGNMENT

SHORT RAIL, CENTRELINE CORRECTION PROCEDURE

Note Gauge Position

Correct DatumCorrect Datum

NOTE GAUGE POSITION ON FIRST GAUGE

Incorrect datumIncorrect datum

SUSPENSION / CROSSMEMBER / CRADLE MUST BEGAUGED AND BE LEVEL WITH THE BASE OF THE

VEHICLE

ANOTHER CRITICAL AREA TO BE GAUGED ISAT THE LOWER CONTROL ARM MOUNTING POINTS

MANY NEW VEHICLES HAVE A SUB-FRAME ASSEMBLYTHAT CAN SUSTAIN DAMAGE OR MOVEMENT DURING

A FRONTAL IMPACT

THIS REQUIRES GAUGING AND MEASURING PROCEDURES BE PERFORMED TO ENSURE CORRECT

ALIGNMENT OF THESE MEMBERS TO THE UNIBODYSTRUCTURE

IF A VEHICLE UTILIZES STRUT TYPE SUSPENSION,GAUGING OF THE STRUT TOWERS IS NECESSARY

CENTRELINE AND LEVEL ARE CRITICAL

CENTRELINE AND LEVEL ARE VERY IMPORTANT

THE CROSSMEMBER PIN, ONCE INSTALLED, WILL ACT AS A GUIDE FOR COMPARING CENTRELINE TO THE

SELF CENTERING GAUGES

IT IS IMPORTANT FOR THE SUSPENSION MOUNTING POINTS TO BE IN THE RIGHT LOCATION IN REGARDS TO DATUM

WIDTH AT THE SUSPENSION MOUNTING POINTS ISANOTHER IMPORTANT AREA OF MEASURMENT

THIS CAN BE A DIFFICULT AREA TO DIAGNOSE, ANDA TRAM GAUGE WITH LONG POINTERS MAY BE THE

RIGHT TOOL

USING THE STRUT TOWER GAUGE AS A TOOL FORMEASURING LOWER BALL JOINTS ON A STRUT TYPE

SUSPENSION.

USING THE CENTER PIN, MEASURE LEFT AND RIGHT BALL JOINT LOCATIONS OFF OF THE PIN, THIS WILLHELP ESTABLISH SAI (STEERING AXIS INCLINATION)BETWEEN THE UPPER AND LOWER STEERING AXIS

POINTS

MEASURING LOWER BALL JOINT LOCATIONSHOULD ALWAYS BE PERFORMED IN ANY FRONTALCOLLISION.

ONCE CHECKED FOR LENGTH, CROSS MEASURE.

FULL FRAME

THE SAME PROCEDURE GOES FOR SUB FRAMEMOUNTED SUSPENSION, CHECK LOCATION OFBALL JOINTS, LENGTH AND CROSS.

SEVERE IMPACT TO ONE SIDE OF THE VEHICLECAN RESULT IN A TWISTED CROSSMEMBER

AGAIN, THIS IS WHY INSTALLATION OF GAUGESIN THE CROSS MEMBER AREA IS IMPORTANT TO A PROPER REPAIR PROCEDURE

PROPER INSTALLATION OF GAUGES TO DETECTCROSSMEMBER DAMAGE

EFFECTS OF

REAR IMPACT HAS CAUSED DATUM MISALIGNMENT•REAR SECTION IS BELOW DATUM HEIGHT AND THEWHEELHOUSE ARCH IS ABOVE

INERTIAL FORCES DEFLECTION THROUGHOUT VEHICLE, RESULTING IN DIRECT AND INDIRECT

DAMAGE

RESULTING DAMAGE IS EVIDENT AFTER THOROUGHGAUGING

IN THIS CASE, THE REAR IMPACT IS TYPICAL WHILETHE FRONT SECTION SUSTAINED VERTICALDEFLECTION RESULTING IN DATUM MISALIGNMENT

TYPICAL DEFLECTION IN A REAR COLLISION

TYPICAL CROSS MEASURING AREAS WHEN CHECKINGUPPER BODY DIMENSIONS

UPPER BODY DIMENSIONS CAN COME FROM SOURCESSUCH AS REPAIR MANUALS, OR BE REFERENCED FROMKNOWN STRUCTURAL AREAS OF THE VEHICLE SUCH AS

SEAT BELT MOUNTING POINTS ETC.

Upper Body Dimension ChartUpper Body Dimension Chart

STRUT TOWER MOUNTING GAUGE CAN BE USEFUL IN MANY LOCATIONS OF THE VEHICLE

EXAMPLE OF DAMAGE ANALYSIS SHEET

Measurement Measurement TrackingTracking

• Benefits– Completely assess

damage – Ability to monitor

progress– Determine pulling

direction– Results in a more

accurate repair

Mitchell System Damage Report

Mitchell System Tram Dimensions Chart

Wedge Clamp Diagnostic SheetWedge Clamp Diagnostic Sheet

By Using a DiagnosticSheet, You canEstablish a RepairPlan

Hein WernerHein WernerDimension SheetDimension Sheet

DingerDinger HoopedHooped

Mitchell System Upper Body Dimensions Chart

MitchellMitchellCD systemCD system