Is your windshield leaking? We can help you diagnose a windshield leak and determine the best coarse of action to repair the leak. Contact us What are the most common causes? Most windshield leaks are usually due to Rust underneath the urethane bond. But in some cases there are other reasons.Rust under the UrethaneBad windshield installationBad gaskets on roof lights Cracks in the panel bond in the rain channels.