STEP THREE

We need to identify the windscreen centre point. The masking tape is going to come in handy here. Using a tape measure, measure the windscreen width at the bottom, from corner to corner. Divide this number by two to determine the centre point, and stick a piece of tape to the glass at this point. Repeat the process at the top of the windscreen, and run the tape straight to the upper halfway point. The vertical tape line will represent the horizontal centre point. In this example, we found that the centre measurement aligned with the upper and lower windscreen trim joins, meaning the reference points were already on the car. Now measure the height of the windscreen — from top to bottom — at this centre point, and divide the number by two to identify the vertical centre point. This is the point that your string line must run from. We marked this with a strip of masking tape, with a marker line identifying dead centre. Alternatively, you can run some string diagonally from each corner; the point where the string intersects will also be your centre point.