1. "Chasing" the threads of an old truck is mandatory. Every threaded hole, every bolt.
2. There is a serious problem with "new" bolts and nuts. Been fighting it for years. Low quality plating. Meaning: too thick/too Chinese. At the slightest hint of tightening up during threading, you must stop and chase the new threads three times. Do the male and female with the same tap and die set. It must go together mostly by hand. Chase the original truck threads first. They do not have an additive style plating (more of a treatment), their only issue is built up rust and grime. That will be cleaned up by re-threading gently (chasing). If there is an "interference" after that, you know its the new stuff. If it won't thread in, throw it away and go to a different hardware store.
3. You should be able to tell fine from coarse from looking down the hole as well as size. Learn to do that if you want to get your gear head card.
