Materials disappear when viewed at an angle

Whenever I move the camera far away enough, the glass on my headlights disappears. How can I fix it?

 

Update:
I somehow fixed the materials but now the lights don't show. They disappear at different at a different angle though

The one on the left is much brighter than the one on the right, and it's only because of camera angle

 

Thats happening with the vanilla cars aswell afaik, its just a bug in the game. Nothing you can do about it.