Minor issue - rear luggage rack

Might seem minor to many of you, but my luggage rack on the back of my 91 lumina is coming off in places.

Specifically, the rearmost two bolts ont he drivers side have lost their nuts entirely, and so the rack vibrates, and there's no good weather seal, so the trunk is starting to get wet. Additionally, i'm going on vacation in a few days time, and may need the rack.

Anyone happen to know what size/pitch the nuts on the rack are, so I can go grab some more. I can't find any listing anywhere, and every search gives me roof racks, or cargo boxes (and I really don't want to undo another one, to try and match it with, that's a recipe for disaster!)

Can't help you on the size, but most parts stores will let you try what they have to see what fits.

Then a smart thing would be to get Nylocks if they have them in that size. Nylocks are nuts with a nylon ring inside that keeps them from backing off once tightened...