Maybe a servo (intermediate/front) or vacuum modulator?
Bryan's vehicles at the Joplin (Full Size) Jeep Refuge:
1988 Grand Wagoneer (on extended loan)
1988 Grand Wagonner (tornado victim)
1987 Grand Wagoneer (formerly mine, now my dad's, also a tornado victim)
1994 Ford Explorer XL rollin' on 1-tons and 40s