Recently, I had just completed rebuilding about 75% of the front end on my '84 SD. The only remaining projects ore shocks and guide rod mounts. I replaced the old wheel bearings with new, packed them with mobil 1 grease. The hubs were tightened not with a dial indicator, but the old "tighten the nut and back it of a bit" technique. The car was driving great and felt much tighter. The guide rods still make a clunk but that's about it. LEt me get to the point: I was driving out about 30 miles and sort of noticed a rhythmic thumping. The thumping graduated to somewhat of a grinding/ scraping/ pulsting sound. It is especially mor noticeable when driving at parking lot speeds. It could be the brakes but I doubt it. I've never had wheel bearings die on me before so I'm not sure of the telltale signs. The tires aren't great and the old centra wheels have two 5mm spacers on them that used to be glued to the wheel but now I just fit them in place.
If it is the bearings, can the situation be rectified, or do I have to start back at square one?

Any and all help is greatly appreciated!