Truss rods are installed in bass guitars to keep the neck straight during shipping and should be removed immediately upon getting them home from the store or after they've been shipped by freight.
Very easy to do.....just take the neck off your bass guitar and hammer out the truss rod with a really skinny screwdriver.
Once the truss rod is sticking out of the neck, use ViceGrips and just keep working it until it comes free.
If it still won't come, try heating it up with a blow-torch ....
You may also need to give the other end of the neck a few really good sharp bangs with a hammer.
Spraying Penetrating Oil down the truss rod hole helps a lot if done the night before.
Before you start the above , take the neck and give it a few good whacks horizontally on a hard surface , being careful that the metal fret inserts don't fall out.
That hurt my brian reeding it.....Brain?.....Yes,...Hert it,you.