Pat,

I had the same problem with the passenger side front seat belt receiver in my '88 760. When I removed it, I found the plastic piece that came loose on mine served as nothing more than a retainer for the spring which pushes up on the release button, and had no part in keeping a passenger safely in the seat. I don't have the skill to paint a picture in words. You'll have to look at what's going on with yours.

I used super glue to reattach the housing with the spring inside. The receiver now works properly. Before you decide to do this, you should look at what has come undone on yours and decide if you have the same situation.

If you're not comfortable making a repair, try auto part recyclers for a replacement.