UNITIZED STRUCTURAL BODY REPAIR
QUESTIONS AND ANSWER S
Question : Unibody
CORRECT ANSWER: Lightweight stamped sheet metal
components that are welded to each other to create a single unit.
Question : Space Frame
CORRECT ANSWER: Body panels can be made from
plastic are steel. Steel may be Mild, Intermediate, or HSS.Panels may hide damage to frame or structure.
Question : Crush Zones
CORRECT ANSWER: Structural components such as rails
are designed to collapse and bend at specific points.
Question : Collision Energy Management
CORRECT ANSWER: Goal is passenger protection. Front
and rear structures act as crush-able energy absorbers.
Question : Direct Damage
CORRECT ANSWER: POI. Easily located and diagnosed.
Question : Indirect Damage
CORRECT ANSWER: transmission of collision energy
beyond the area of immediate impact. Examples; Split seam sealers, pulled spot welds, misaligned panels, buckles in steel, cracked glass, and cracked or chipped paint.
Question : Passive Restraint Systems
CORRECT ANSWER: Must have service manual. No two
are alike.
Question : Datum
CORRECT ANSWER: Imaginary plane or line beneath the
vehicle. Measures height.
Question : Centerline
CORRECT ANSWER: Vertical plane that passes from the
front of the vehicle to the rear. Measures Width. May have stamped marks on vehicle body structure. Is confirmed by referencing at last 3 width measurements in the undamaged portion of the vehicle.
Question : Zero Planes
CORRECT ANSWER: Vertical plane that passes from side
to side. Confirmed by measuring 3 length measurements from the undamaged portion of the vehicle.
Question : Symmetry
CORRECT ANSWER: Equal on each side of the vehicle.
Question : Asymmetrical
CORRECT ANSWER: Unequal on each side of the vehicle.
(spare tire well)
Question : Reference Points
CORRECT ANSWER: Bolts or nuts, Holes, Mechanical
attachment points, Edges of panels, Door strikers, Corner of openings. Common tolerance is =/.3mm (1/8) or all the way to 1mm (1.32).
Question : Loaded Measurements
CORRECT ANSWER: Drivetrain In
Question : Unloaded Measurements
CORRECT ANSWER: Drivetrain out
Question : Point to Point Measurements
CORRECT ANSWER: shortest distance between 2
reference points. AKA "as the crow flies". Uses tram or steel tape measure.
Question : Datum Measurements
CORRECT ANSWER: Taken at Datum plane, height
differences between reference points. Laser measuring system
Question : Computerized Measuring System
CORRECT ANSWER: compare data stored in a software
program or a central database. Get hard copy of measurements. Can watch while pulling.
Question : Steel
CORRECT ANSWER: Cannot know what kind by visible.
Must check service manual.
Question : Tensile Strength
CORRECT ANSWER: Amount of pressure/force necessary
to fracture or tear steel.
Question : Yield Strength
CORRECT ANSWER: Amount of force/pressure necessary
to deform steel permanently.
Question : PSI
CORRECT ANSWER: Pounds per inch /// tensile and yield
strengths are expressed. Higher the number the stronger the steel.