I have 4" peep mirrors on my coupe and, like you, the right one was useless. A buddy gave me a tip that worked great and looks good too. I bought a generic 4" convex mirror, available anywhere, even Walmart. I then broke out the original glass in the peep mirror, then use silicone to glue the convex mirror in its' place. It looks good because it doesn't look like it's stuck on there, and best of all, it works!