1991 Chevy k1500 rear pinion seal replacement?

I recently noticed that my rear end pinion seal is leaking, i have a 1991 k1500 half ton with a 8.5 inch rear end, i started by disconecting the drive shaft with the u joint, im not sure on what to do next, do i have to remove the carrier and then pull the pinion? or can i take of the big bolt where the u-joint connects which i think is called the yolk and be able to change it from there, im a pretty good at turning a wrench but i have brand new rear end oil in it and i dont wanna have to do any extra work if i dont have too, and help would be highly appreciated