65 Dart Horn Problems

I don't know the name of the little roller contact that makes contact with the horn contact ring but I'll just call it the roller. The roller when touching ground works; no short in the column. The caulking didn't work, horn grounds immediately when the wheel is tightened down. So I took it all apart and used brush on electrical tape. It insulated the contact ring fine, but wasn't thick enough to allow the contact ring to touch the roller so I took it all back apart. Now the only option I can think of is to find an original plastic gasket thingie or fabricate one out of a sheet of abs or the like.