scaping start and brake switch button replacement

[Kaiylans240]

I have a 91 240sx SE. The engine keeps making a strange scraping noise at startup every time. However, it runs fine otherwise. No one I have talked to has any idea what would make the scrape or if is something that needs attention immediately or not. Any ideas?

Also, I am trying to install the button for the brake light switch, but can't figure out how. I have the part, but am getting frustrated. Anyone know how to replace it, or a place i can get a good diagram?

Thanks