well the originals have lasted since new in '93 but it appears its time for new, found this major crack in the l.f. rotor when putting on my new lockout hubs. going to drill holes in the new ones to fasten the hubs to the rotors with screws. i was wondering why i was getting a pulsating pedal under heavy braking, guess i know now. ive not seen one do this before. its a little hard to see in the photo, crack is at about the 11 o'clock postion. at least new ones werent too bad, about $30 per rotor. napa had some high-performance rotors for $130 a piece, looked like racing rotors with the grooves and cooling holes. if the truck were newer i might have considered it, but im not convinced it would be much of a upgrade for the $ id be spending. now for warmer weather so i can do the job. im also going to take the spindles off and inspect the spindle bearings and axleshaft U-joints. but not at 30 degrees. heres a pic:

Thats a major crack.
I've got an 87 B II that needs rotors.
They started pulsating some time ago but I probably put about 600 miles a year on it , so it dosn't bother me to much.

Just did my 2005 rotors and man what a difference it makes - and mine didn't have any cracks lol

Might wanna swap out pads for new ones as well - go for ceramic!