The hard part is removing/replacing the yokes. Overtighten and you can compress the crush sleeve too much. I do not recommend using an impact for them, I take the nut off marking it and counting revolutions to replace it exactly as it was. Other than that, get a seal puller, looks like a plate steel hammer with a pick on each end, you use the appropriate size hook to get on the inside of the seal and pop it out. Carefully tap a new seal in and replace the yoke, just be sure to wipe a little oil on the seal and carefully work the yoke in so you don't damage the seal and your done. Sounds harder than it is but it is a simple job.