MITO Collision Repair L4 flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Datum point

An OEM-specified reference location on the vehicle used with a measuring system to confirm that the body structure sits in its designed position in three planes.

Centreline

The imaginary fore-aft vertical plane through the middle of the vehicle. Symmetrical measurements are compared left and right of it to detect sway or diamond damage.

Control point

A structural reference point with a published OEM tolerance, commonly about plus or minus three millimetres. It must be verified before new panels are aligned or welded.

Crumple zone

A deliberately deformable front or rear body section that absorbs kinetic energy in a collision, reducing the force transmitted to the occupant cell.

Occupant safety cage

The rigid passenger compartment structure designed to resist deformation. Damage here requires measurement against datum dimensions and OEM-approved repair methods.

Unibody construction

A design in which the body shell and floor form the structural frame. Impact loads travel through the shell, so straightening must follow measured OEM dimensions.

Body-on-frame construction

A design with a separate ladder frame carrying the load and a body mounted on top. Frame straightening and body alignment are assessed separately.

Press-hardened boron steel

Ultra-high-strength steel with a martensitic structure formed in the press. Most OEM procedures prohibit straightening or heating it; the part must be replaced.

Heat restriction on HSS

High-strength steels lose strength when heated above roughly 200 degrees Celsius. OEM repair information specifies whether heating is allowed and at what limit.

Sectioning

Cutting and joining a partial replacement panel. Permitted only at OEM-approved locations, using the specified joint type, with corrosion protection restored inside and outside.

Squeeze-type spot welding

The standard joining method for steel body panels. Current, time, electrode force and tip diameter must follow the OEM weld schedule and be verified by test coupons.

Diamond damage

A condition where one side of the vehicle is displaced rearward relative to the other, making the centreline skew. Detected by comparing diagonal and centreline measurements.

Sway damage

Lateral displacement of the body structure, often from a side impact. Found by comparing width measurements against OEM datum dimensions on both sides.

Mash damage

Vertical collapse of the structure, typically from a rollover or heavy top impact. Identified by height measurements falling outside OEM datum tolerances.

Twist damage

A condition where the vehicle is rotated about its fore-aft axis so one corner sits higher than the opposite corner. Detected by comparing height readings at matched points.

Three measuring planes

Length, width and height. A structure is confirmed straight only when reference points match OEM datum dimensions in all three planes, not just one.

Repair sequencing rule

Structure is measured and pulled first, bolt-on panels aligned second, and refinishing performed last. Painting before structural alignment hides misalignment under the finish.

SRS deactivation

Disabling the supplemental restraint system per OEM procedure before repair, including battery disconnect and waiting the specified time, to prevent accidental airbag deployment.

High-voltage safety

On hybrid and electric vehicles, the HV system must be de-energised and verified dead by a qualified person before any structural or panel work near HV components.

Pre-repair damage record

Documentation of existing damage, paint condition and panel gaps made before work begins. It protects both the shop and the customer in later disputes.

Galvanic corrosion

Corrosion caused by joining dissimilar metals, such as steel fasteners in aluminium panels. OEM procedures require isolating barriers and correct fasteners at such joints.

Aluminium repair isolation

Aluminium body repair requires a separate area, dedicated tools and dust extraction, because steel particles embedded in aluminium cause severe galvanic corrosion.

Weld bond

A joint combining structural adhesive with spot welds or rivets. OEM procedures specify adhesive type, bead pattern and weld spacing; omitting either part weakens the joint.

Panel gap measurement

Checking consistent gaps and flushness between adjacent panels. It confirms structural alignment and is recorded before and after repair as a quality control step.

Pre-stretch in pulling

Applying a controlled pull beyond the original position before releasing, to counteract elastic spring-back in the steel so the structure settles at the datum position.

Anchoring for pulling

Securing the vehicle to the bench or frame machine at OEM-approved anchor points so pulling force is transferred without damaging the structure or the fixtures.

Supplementary restraint inspection

After a collision of sufficient severity, SRS components such as sensors, pretensioners and the control module are inspected or replaced per OEM criteria, not just reset.

Corrosion protection restoration

Reapplying primer, seam sealer, cavity wax and anti-chip coatings after welding or sectioning, matching the original protection so the repaired area does not rust from inside.

Battery disconnect sequence

Following OEM order for disconnecting and reconnecting the battery, including waiting times for capacitor discharge, so modules and safety systems are not damaged or triggered.

OEM repair information

Manufacturer-published procedures covering materials, sectioning locations, weld schedules, tolerances and replacement rules. It overrides general workshop habit whenever the two conflict.

Structural vs cosmetic panel

Structural panels carry load and affect crash performance and must meet OEM repair rules; cosmetic panels affect appearance only and can be replaced more freely.

Destructive weld test

Peeling or twisting a test coupon made with the same welder settings as the repair, to confirm weld nugget size and penetration before welding the actual panel.

Measuring system calibration

Verifying the bench or measuring equipment against a known reference before use. Uncalibrated equipment makes every datum reading unreliable regardless of technique.