Windscreens

The windscreen of a modern car contributes to the overall strength and rigidity of the vehicle’s body and forms part of the vehicle’s passenger cell.

In some vehicles the passenger side airbag is designed to deploy against the windscreen glass, which guides it into the correct position in order to provide maximum occupant protection.

Windscreens that are severely damaged not only obscure the driver’s vision, but also can weaken the vehicle’s structure and affect the way passenger side airbags deploy.

Some windscreen damage can be repaired however other types will necessitate replacement. Windscreen repairs are recognised in Australian Standards and come under AS/NZS 2366. This standard sets out the repair methods, repair materials and types of damage that can be safely repaired. Many windscreen suppliers also carry out repairs and are happy to provide advice about what can and can’t be repaired.

Where a windscreen is unrepairable, the glass is removed by cutting the bonding material (glue) that holds it in place; or much less commonly these days, removing it from its rubber.

For bonded windscreens the opening is prepared and new bonding material is fitted. The new glass is then fitted into the opening. For rubber-mounted windscreens the new glass is fitted into its rubber and the body opening and is sealed to prevent water entry.

Vehicles fitted with a windscreen rubber can be used immediately the new glass is fitted. However vehicles with bonded windscreens may need to stand for several hours until the bond cures to full strength. In part, this is to ensure that the windscreen’s bond is sufficiently cured to withstand the forces of a deploying airbag.

Water leaks

Older windscreens with rubbers were far more prone to leakage than bonded screens due to deterioration of the rubber seal, though in many cases they could be easily resealed.

Leaks from bonded screens are more difficult to fix as often the bond has broken and the windscreen will need to be removed and rebonded. However removing a windscreen can be risky as there is a chance that even an undamaged screen may break during removal.

The other common leak source is rust in the windscreen opening, which will need to be repaired before the windscreen can be refitted.

Roadworthiness issues

Queensland Transport requires windscreens, windows and associated components to be in such a condition that the driver has a clear field of view under the normal range of climatic conditions.

General requirements include:

• Glass must be of an approved type
• Glass must not be badly chipped, scored, cracked, sandblasted or otherwise damaged so as to impair the driver’s vision or damage wiper blades
• Tint films must comply with the requirements outlined above and must be free of bubbles and scratches that would significantly affect the driver’s vision
• Windscreen repairs must comply with the relevant Australian Standard.

Note that these requirements are only a brief outline. For more details consult Queensland Transport or RACQ Technical Advice.