No this is a new installation. I thank you for the info. Being so close to Christmas I probably won't be able to do what you suggest until after the holidays. I know what you mean by being out of sync., but I'm wondering if there is any way to run them into a common sync? Reason for asking is that these are mounted on a '32 Tudor and the windshield is not that big, so there might be an overlap of the blades which could cause a problem.