Adjust Headlights S1

The factory declination angle of the S1 headlights is 1.5º degrees. However, because the headlights are quit low to the ground, this angle doesn’t provide much forward illumination, so an angle of 1.1-1.2º is preferable for daily driving, but may be marginal for an MOT/CT pass.

To check the alignment

1. Set tyre pressures correctly.
2. Park the car on a very level surface 5m away from a vertical wall. Ballast the driver’s seat with 75KG passenger to get accurate readings but I don’t think this is strictly necessary.
3. Turn on the headlights in low beam. You should see a pattern like ___/___/ for LHD or \___\___ for RHD projected against the wall.
4. Put a tape measure just in front of each headlight so that the brightest part of the beam focuses on about a 1cm strip of the tape measure. Note the height where the brightest part ends. This is the reference height for the beam. The beam should be angled downwards from this height to avoid dazzling oncoming drivers.
5. Cover one light with a shop cloth so that the other headlight clearly projects a beam against the wall.
6. Measure the height of the beam against the wall where the horizontal line is projected, just where the beam starts angle upwards. This is the reference height. It is useful to mark this spot with a piece of tape for reference.
7. If the wall is 5m from the headlamp, the beam horizontal line projected on the wall should be 12 cm below the reference beam height for 1.5º or 10cm for 1.2º dip angle. It is useful to mark the target height with a piece of tape for reference. If the distance from the headlights to the wall is not exactly 5m, use the TAN function on a calculator to determine the correct drop.
8. You can adjust the height of the beam to hit the target height by removing the radiator shroud and reaching underneath the headlamp to turn the butterfly nut clockwise to raise the beam or counterclockwise to dip the beam.
9. Repeat steps 5-8 for the other headlight.

The beams should also be projected parallel with the centerline of the car. To check

1. Measure the distance between the centerlines of the headlights
2. The centerline of each beam projection is the corner where each beam starts to angle up at 15º.
3. With headlights projected on the wall, measure the distance of the centerlines against the wall. This distance should the same as the distance between the centerlines of the headlights, and the centerlines should be equidistant from the centerline of the car.
4. Adjust by turning the butterfly nuts on the side of the headlamp brackets.