A report back. I got it to it's destination, but in this Texas heat, no telling what became of the bearings themselves. I could only keep my hand on the hubs for about 4 seconds. Too hot, I know. Before it moves again, I slip out the axles and do the repack. I suspect too much preload and gear oil through whatever seal was there, which washed out the grease, or a combination of the above. My purpose in posting this, is that our trucks are over engineered, which is a great thing. All of this while pulling my trailer with 7000 pounds of mesquite wood on it. I refused to load the truck bed with more wood because of the bearings.
If the seals leak badly enough to wash out the grease, you will usually have great wet drool marks down the sides of your tires. It isn't something you can miss.
Timkin roller bearings are perfectly happy with differential oil as a lubricant. They wouldn't run hot because of running a thinner lube than GAA.
Hot hubs are caused by: 1) excessive bearing tension. 2) dragging brakes. 3) excess grease. and a distant 4) excessively thick grease.... I'm not sure where you would find an excessively thick wheel bearing grease.
I pack the bearings with a #2 NGLI wheel bearing grease, or GAA. I do the packing by scooping a blop of grease into the palm of my hand, and kneeding as much grease as I can into the rollers with my fingers. I wipe a little grease on the seals, and butter in enough grease to fill in the sides of the cages/rollers, and that is it for the grease. It takes several minutes to pack the grease into the bearing. Using a bearing packing attachment is fine too... If you have one big enough. Do not stuff 5 lbs of grease into every nook and cranny in the hub. If you do that, you will cause the grease to be pumped around by the roller bearings, and that makes lots of heat. The only purpose for the grease is to lube the roller bearing cage, to provide a film of lubricant that cushions the rollers against the races, and to keep the dust and dirt away from the rollers... a problem that is not so critical with modern seals... more so with the old felt seals. The grease will push out of the way of the rollers almost immediately in operation. The grease acts as a sponge full of oil, and keeps a wet oil film on the bearing surfaces. That is all.
I put the hub back on the spindle, and tighten up the nut a bit beyond snug, while rotating the hub in each direction. Tightening a little more each time until I feel bearing rumble and drag. (The torque specs in the TM are really only good for brand new bearings and races, and for mechanics that can't be taught how to feel when a bearing is right. ) I then loosen the nut until the drag and rumble is gone, usually 1/8 to 1/4 turn, and there is a barely perceptible click feel when I attempt to "steer" the axle by pushing and pulling on the drum. You can't hear it, or see it, but you can just barely feel a little click as you change directions. Sometimes you have to repeat the tightening and loosening of the nut several times until you get the right feel.
Then is when you put on the lock tab, and tighten up the outer nut to spec. Tightening the outer nut will take up some of the "lost motion" set into the bearing when you adjust it, but I believe there should still be a very tiny amount (others disagree). If the bearing regains the rumble feel after you tighten the outer nut, it is adjusted too tight and you need to loosen it... and do the inner nut adjustment over again, looser this time.
One thing to note: I have never had a bearing fail from being adjusted a tad loose.... But they always fail when they are too tight.
-Chuck
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. They need to do a better job of QC at the factory...
