Windshields

Windows directly affect visibility, structural safety and climate control in the cab of MAN and Mercedes trucks, buses and vans. This subcategory includes windshields, side windows, door windows, rear windows, fixed body windows and windows for bus doors or emergency exits. Depending on the application, these may be laminated safety glass for windshields or toughened safety glass for side and rear windows. A laminated windshield generally consists of two glass panes with a PVB interlayer (polyvinyl butyral), which retains glass fragments in the event of breakage. Toughened glass, on the other hand, breaks into small, less sharp fragments.

The correct window is determined using the vehicle chassis number. Visual comparison or selection based solely on the model name is never sufficient. Within models such as the MAN TGL, TGM, TGS, TGX, TG3 and TGE, or the Mercedes Atego, Actros, Arocs, Sprinter and Vito, glass dimensions, curvature, tint, mounting method and cut-outs for sensors vary by model year, cab variant and equipment level. For MAN Lion’s City, Lion’s Coach, Neoplan coaches, Mercedes Citaro, Intouro and Tourismo models too, windows are linked to a specific body version, door position and emergency exit configuration.

Stone chips in the driver's field of vision, star-shaped cracks, edge fractures and delamination of the PVB interlayer are typical types of windshield damage. A small impact outside the critical field of vision can sometimes be repaired, provided the damage does not extend to the edge and no moisture or dirt has penetrated between the glass layers. Cracks originating from the edge often indicate stress caused by body torsion, incorrect installation or a damaged window aperture. Replacement is then the technically safe solution.

Side windows frequently suffer from scratches caused by worn window guides, breakage following burglary and poorly functioning window mechanisms. For electric door windows, always inspect the cables, guides, lifting cables and retaining clips before fitting a new window. A window that operates stiffly may break again if the window regulator pulls at an angle or if the guide rubbers are dirty and hardened. On fixed windows, aged sealing profiles, dried-out sealant joints and corrosion around the window flange often cause water ingress. This leads to moisture in the cab, corrosion, fogged-up windows and faults in wiring harnesses or control modules.

First clean the window and inspect it under strong lighting for crack patterns, scratches and white edges around the interlayer. Then check the window edge, trim strips and bonding for signs of detachment. If a leak is suspected, carry out a targeted water test using low, constant water pressure; do not use a pressure washer, as this can force water through an otherwise sound seal. Check the interior for traces of moisture around the A-pillars, dashboard corners, headlining and door panels. A windshield fitted with a camera, rain sensor or light sensor must be calibrated after replacement in accordance with the vehicle specification.

Replacing a window requires a clean, dimensionally accurate window aperture. Remove old polyurethane adhesive in a controlled manner, treat paint damage to prevent corrosion, and use only the specified primer, activator and window adhesive. The adhesive bead must have a consistent height and a continuous contour; interruptions cause leaks, wind noise and insufficient bonding. Observe the safe drive-away time of the polyurethane adhesive used, which depends on temperature and humidity.

After installation, check the fit in relation to the bonnet, doors, roof panels and windscreen wipers. Replace damaged window trims, clips, cover profiles and seals at the same time. Braem can support you with correctly fitting cab parts and windows for an efficient repair, helping to minimise downtime caused by visibility issues, leaks or glass damage.