fixing rubber trim in hatch

By the book, his advice was correct: the back door weatherstrip, part number 67881-47051, is shown in Toyota’s parts catalog (Figure 67-08, Back Door Panel & Glass) and Repair Manual (more info) as a non-reusable part: if it has to be removed for any reason, even if undamaged, it’s replaced with a new one, not reused or repaired.

The Repair Manual explains how to do the installation, which involves matching some alignment marks but not the use of any adhesive. It’s supposedly a quick job: one edition of Toyota’s Flat Rate Manual allows 0.1 labor hours for removal and replacement (operation number 642101, ZVW50 series).

The list price for the part at U.S. dealers is $175.70, but it also fits cars sold in Japan, where it’s available for ¥7300, or about $54 at this writing; even with international shipping costs, you’d come out ahead by purchasing from an exporting company such as IMPEX JAPAN, JP-CarParts.com, or Amayama Trading.

I suppose you could try to use an adhesive to mend a damaged weatherstrip or secure it in place, but without knowing what kind of rubber it’s made of—something Toyota doesn’t tell us—it’s difficult to make a specific recommendation. An adhesive that works well with neoprene, for example, might be totally incompatible with EPDM. I’d also be concerned about the quality of the resulting seal; despite the song, Los Angeles gets enough rain that you don’t want water to enter and eventually cause corrosion.