I would think the 86 and 87 should be close/same. I wore a dunce hat when I changed mine by trying to shortcut and slide over antena and force into hole from outside - that doesn't work.
Retract antenne, remove interior trunk, remove ground cable and two mounting screws from motor assembly. Replace seal from inside (kinda snaps into place). and backtrack on the above instructions. I spent probably and hour trying to grease up the new seal and slide from the outside before taking the 20 minutes to do it correctly by removing the components.
