I have a recurring problem with my '86 k5 blazer. Once it hits highway speed, the truck becomes extremely unstable if it hits a bump. On slow speeds after the truck has been running for a while, when I make a turn at a traffic light (mostly rights) the truck pulls hard to the right almost feels like the wheel is rolling of the truck. I also noticed that when I got home the hubs were scalding hot to touch.

This happend a few weeks back, so I thought the front end needed service since it was all the orginal pieces. That said, its got all new tie rod ends, center link, pittman arm, steering stailizer etc. The factory auto locking hubs were replaced with a set of Warn Manual locking hubs. I am running 33x12x15 so the tires are not enourmously huge. We jacked it up this evening to check for play in the front universal or wheel bearings, and found none.

I understand that this may be common on the older live axle 4x4's. Any thoughts?

Before I start getting suggestions, I have already

John
The front hubs getting hot indicate either a bearing problem (may be adjusted too tight or insufficient grease) or brakes dragging. I would pull the hub and clean, inspect the bearings (if discolored discard) and repack with fresh correct lubricant and seal.
While it is apart inspect the brakes (in particular for sticky wheel cylinder) or hub lubricant.
Tony

and don't forget to repack the small torrington bearings inside the spindles. it shouldn't be the cause of your wobble but it is often neglected when packing bearings.

it sounds suspicously like a loose end of the steering connecting rod

I'd replace the brake hoses.

There wasn't really any play in the wheel when we raised it to indicate a wheel bearing had gone bad,however with all the heat I have to assume that the grease broke down so we'll pull them and repack. I am begining to think that it very well might be a caliper that could be sticking. Who knows how many times the calipers were rebuilt since the in the last 30 years. The hoses are all new so I couldn't see one of those giving me trouble. As a whole system, then entire brake system was replace before the winter, new lines, master, hoses etc.