snyderiii

I wondering how this trail is supposed to be working? It slides, kinda. But looking at the bottom of this, it appears there should probably be another spring on the left side. Not sure what it looks like, and therefore a suitable replacement or maybe even the part number. But even then I won't know how and where to connect it. Any help would be much appreciated.
This is the passenger seat on my 88 4runner.
Thanks