Caster bolt source

There never was a two piece design. Before 97 they used spindles. And after upper and lower arms. This is a USA vehicle?

Yes it is a USA vehicle as I am located in central AR. It is a two piece design, look at ebay and search "explorer control arm" for an example. You will find pictures with two different looking pieces. The piece on the left is the half of the passenger side upper control arm.

There is a very real need to check our facts before posting a reply. FWIW, even after 97 they still used spindles (steering knuckles) but what on earth does that have to do with the two piece control arm which was only fitted on the right hand side and put there in order to adjust caster split. This two piece design upper control arm was fitted to both two and four wheel drive models though I am unsure if they are interchangeable.

Original poster... I do not recall this bolt ever being serviced separately. You might check at your local alignment shops to see if someone has had a right upper ball joint replaced recently and may be able to salvage a bolt from a customers control arm.