Driver side view mirror is loose (help)

[Juzjon]

Yesterday my driver side mirror became loose. I don't know how or why but all of a sudden it swivels 180* and is not locked down to it's base. Has a pin or something fallen off? Is there a way to inspect and repair it without damaging it? Any advice would certainly help. It is a 2000 Disco II SD.

[kh500]

I couldn't fix it. so, I got the used one from ebay.com for $45.
Carefully remove triangle shape cover and insulation material inside of door.
Then you can access three mounting bolts.
It's 10min job.