Looking for the nut size for the radius arm on my 2wd f250 doing the bushings and none of the part stores have the nuts

 

They don't normally need to be replaced, what's wrong with yours?

 

nothing, just old and rusty, replacing all the hardware since everything is apart as cheap insurance. got the old ones off easier then expected, there 3/4" course thread got some locknuts from the parts store, unfortunatly after getting the brackets off they look like swiss cheese

 

I would reuse the OEM ones.