A triangulation method for replacing the windshield of a vehicle, said method is characterized by the steps of: providing a vehicle with an existing windshield in a windshield opening, said windshield having a plurality of identifiable elements selected from a group consisting of structural design features, markings, and pre-applied features, a replacement windshield for said vehicle, at least one suction cup assembly including a suction cup and pump assembly, and at least one alignment guide in association with said at least one suction cup assembly (6, 8) for providing a windshield triangulation assembly; selecting three of said identifiable elements; securing said at least one suction cup assembly to said existing windshield adjacent to at least one of said selected identifiable elements and also moving said at least one alignment guide relative to said existing windshield and affixing each said at least one alignment guide adjacent to a different one of said selected identifiable elements, thereby creating reproducible 3-point triangulation alignment information in the windshield triangulation assembly; removing said at least one suction cup assembly and at least one alignment guide from said existing windshield while preserving said reproducible 3-point triangulation alignment information in the windshield triangulation assembly; and applying said at least one suction cup assembly and at least one alignment guide to said replacement windshield, transferring said reproducible 3-point triangulation alignment information to said replacement windshield via the windshield triangulation assembly, wherein said transferred reproducible 3-point triangulation alignment information allows said replacement windshield to be accurately installed in said windshield opening of said vehicle. providing a vehicle with an existing windshield in a windshield opening, said windshield having a plurality of identifiable elements selected from a group consisting of structural design features, markings, and pre-applied features, a replacement windshield for said vehicle, at least one suction cup assembly including a suction cup and pump assembly, and at least one alignment guide in association with said at least one suction cup assembly (6, 8) for providing a windshield triangulation assembly; selecting three of said identifiable elements; securing said at least one suction cup assembly to said existing windshield adjacent to at least one of said selected identifiable elements and also moving said at least one alignment guide relative to said existing windshield and affixing each said at least one alignment guide adjacent to a different one of said selected identifiable elements, thereby creating reproducible 3-point triangulation alignment information in the windshield triangulation assembly; removing said at least one suction cup assembly and at least one alignment guide from said existing windshield while preserving said reproducible 3-point triangulation alignment information in the windshield triangulation assembly; and applying said at least one suction cup assembly and at least one alignment guide to said replacement windshield, transferring said reproducible 3-point triangulation alignment information to said replacement windshield via the windshield triangulation assembly, wherein said transferred reproducible 3-point triangulation alignment information allows said replacement windshield to be accurately installed in said windshield opening of said vehicle.