i used aerosolized Tri-Flow, but i went at it from both ends soaking the cable rather than the housing, and worked the cable to move the lube along the inside of the housing......prolly cheaper to replace the lines and be done with it.
LMC truck (
www.lmctruck.com) part numbers:
f250/f350 2wd 1986 (til february) 45-3766 and 45-3767 (u need both)
f250/f350 4wd 1986 (after february) to 91 45-3768 and 45-3767 (need both)
f250/f350 2wd/4wd 92-94 45-3774 and 45-3775 (yep you guessed it, need both)
ALSO.... the ebrake arm inside the drum could be corroded and sticking