Hi Jeff,
Not certain exactly what you mean about the brackets being gone...I've never seen that happen before but attached is a set of instructions I wrote on how to repair the seat sliders. It may be helpful. Hope so.
Attachments
AD seat slider repair.docx (1.5 MB, 40 downloads)
SHA1: 9c91b725fd95958b466b8b437067606d0d2b6bd7

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end