UNITIZED STRUCTURAL BODY REPAIR
QUESTIONS AND ANSWERS
Unibody - correct-answer-Lightweight stamped sheet metal components that are
welded to each other to create a single unit.
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.
Crush Zones - correct-answer-Structural components such as rails are designed to
collapse and bend at specific points.
Collision Energy Management - correct-answer-Goal is passenger protection.
Front and rear structures act as crush-able energy absorbers.
Direct Damage - correct-answer-POI. Easily located and diagnosed.
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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.
Passive Restraint Systems - correct-answer-Must have service manual. No two are
alike.
Datum - correct-answer-Imaginary plane or line beneath the vehicle. Measures
height.
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.
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.
Symmetry - correct-answer-Equal on each side of the vehicle.
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Asymmetrical - correct-answer-Unequal on each side of the vehicle. (spare tire
well)
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).
Loaded Measurements - correct-answer-Drivetrain In
Unloaded Measurements - correct-answer-Drivetrain out
Point to Point Measurements - correct-answer-shortest distance between 2
reference points. AKA "as the crow flies". Uses tram or steel tape measure.
Datum Measurements - correct-answer-Taken at Datum plane, height differences
between reference points. Laser measuring system