Headlight Restoration in Yorba Linda

Because the yellowing is not on the lens, it is the lens. Polycarbonate oxidizes when exposed to ultraviolet light, turning yellow and then hazy. The factory hard coat exists specifically to prevent that, and once it has failed the material underneath is unprotected.

Polishing removes the oxidized layer and any remaining hard coat with it. The result looks excellent for a few weeks and then degrades faster than the original did, because the original at least had a coating for the first several years.

This is why kiosk and driveway restorations have such a poor reputation. The work is not incompetent, it is incomplete. Removing the damage without replacing the protection guarantees the customer will be back, and in Southern California ultraviolet conditions that can be as little as six months.

Staged wet sanding, working from a grit aggressive enough to remove all the degraded material through progressively finer grits until the sanding scratches are fine enough to be removed by polishing. Skipping grits leaves deeper scratches that the next stage cannot remove, which is why a hurried job looks hazy in direct sunlight.

Then thorough cleaning and drying, because any residue or moisture trapped under the clear will show permanently. Masking of the surrounding paint follows, since the clear will bond to whatever it lands on.

Then the coating. A dedicated ultraviolet resistant clear, either a wipe on system or a sprayed automotive clear, applied evenly and allowed to cure fully. That layer is what carries the ultraviolet load instead of the polycarbonate, and it is the difference between a repair that lasts years and one that lasts a season.

• Staged wet sanding without skipping grits
• Complete removal of degraded material, not just the surface haze
• Thorough cleaning and drying before any coating
• Surrounding paint masked, since the clear bonds to anything
• Ultraviolet resistant clear applied and fully cured

When the damage is internal. If the lens is hazy on the inside, from moisture ingress through a failed housing seal, no amount of external work will touch it. That is a housing seal failure and the assembly needs resealing or replacing.

When the lens is cracked or crazed. Fine crazing across the surface indicates the polycarbonate itself has degraded deeply, and sanding that far removes so much material that the lens becomes optically distorted. Replacement is the answer.

And when the reflector behind the lens has failed. Reflector coating degrades from heat, particularly on housings that have had over specification bulbs fitted, and a perfect lens in front of a dull reflector produces a poor beam. Cleaning the outside of that assembly does nothing useful, and on a vehicle that is driven at night it is worth knowing before spending money on the lens.