Vehicle Body Alignment, Fitting and Assembly
This domain covers structural measurement, panel alignment, fitting and final assembly. The exam tests whether you can check a vehicle's geometry, fit panels in the right order, and hand over a car whose doors, lights and trim work correctly.
Core rules
- Establish the datum and centre line before measuring. Use the manufacturer's control points and a measuring system or frame rack; compare diagonals and symmetry, not just one panel gap.
- Repair structure first, then bolt-on panels. A door cannot be aligned correctly if the aperture or hinge pillar is out of position.
- Check gaps and flushness with a gap gauge and straight edge. Aim for the manufacturer's specification and make the gap even along its length; a tight gap at one end and wide at the other shows hinge or panel misalignment.
- Adjust hinges, strikers, latches and shims in small steps. Tighten bolts to the specified torque and recheck operation after each adjustment.
- Fit doors, bonnet, boot or tailgate, bumpers, lamps and trim in a logical sequence. Check that handles, locks, windows and seals operate without rubbing.
- Protect newly painted edges and use tape or soft pads when fitting. Do not force clips into fresh paint.
- After assembly, carry out a water leak check, road-test where permitted, and recalibrate driver-assistance sensors such as cameras or radar behind bumpers and windscreens when the maker requires it.
Worked example
A door is proud at the rear edge but flush at the front. The reasoning is not to bend the door. Check the hinge alignment, the striker position and the rear aperture. If the front gap is correct and the rear is out, the hinge may need a small shim or the striker may be holding the door out. Adjust one variable at a time, tighten to torque, and recheck the gap and latch operation.
Traps that cost marks
Adjusting a painted panel with force, aligning bolt-on panels before structural correction, over-shimming, ignoring latch operation, and forgetting sensor calibration after bumper or glass work.