The dash rattles and there is a point where metal and metal at bouncing together. Need some help determining the replacement fastener or bolt size for this treaded post.
Oh man, I wish I could tell you. I remember seeing a post about this somewhere on the internet, but can't remember what the size was. Maybe @mrblaine or @Jerry Bransford can help.
I have multiple drawers full of old nuts and bolts, so I end up trying 15-20 and narrowing it down that way. If you have a set of calipers you can measure to get an idea. If it's like most cars it's a 10mm nut with whatever standard threads they all have around the entire car. Is there a matching one on the other side of the vent you could take off and take with you?