No matter how much time I put into packing bearings, I can never get them as smooth rolling as the shop guys do. The best I can get my (2x4) fronts is about one revolution of free spin after I pack them, and the shop packed bearings will go 3-4 revolutions. ( A "Spin" is a jacked up tire spun by hand Price-is-Right style)

What's the secret to it? I have a bearing packer that I use but it'll still only get the 1 revolution.

 

How freely the wheel spins has alot to do with the bearing preload. Also a freshly greased bearing is going to have a slight amount more drag than a bearing that has been run in. Try driving your outfit for a while with the preload set properly and then jack it up and do your spin test again. You'll notice a difference I think.

Randy

 

What is preload exactly? I'm guessing it's some partial weight put on the bearing for breaking it in, but I don't see how that can be done without some special piece of equipment.

 

Preload is the amount of pressure aplied by the nut to the bearing assemby. You don't really need special equipment, just a torque wrench. My Chilton's manual says torque the bearing nut to 17-25 ft. lbs.
If you don't have a torque wrench, just tighten the nut down gradually while tuning the wheel back and forth until it starts to drag, the back it off just until it turns freely, tuning the wheel the whole time. Back it off until you can get the cotter pin in.
That's how we were taught in HS Auto Mechanics.

 

ah, the nue that retains the bearings and rotor on the spindle. I had them both at 25 lbs and backed off until the cotter pin could be inserted through the locknut & nut when they're pushed together. I don't think that was the problem.

I know I'm missing something because the bearings now squeak (1000 mi later) and have tough rolling resistence (can keep the truck with a freshly rebuilt 351 and auto tranny from going forward with no brake while in gear.

 

Sounds like you had the pre-load set correctly.
Have you had the bearings off the truck to check for galling? Maybe some sand or dirt got in there?
You may want to invest in a bearing packer. They don't cost too much and do a better job of packing the bearings than is possible by hand. Are you sure it's the bearings and not the brake rotor being warped or the caliper being stuck?

 

Rotor and caliper (and rubber hose brake line) were replaced (which is why I repacked the bearings) for that very reason. The difference is that the brake fluid would boil over the master cylinder when the brakes were not disengaging and I haven't noticed that symptom since i used braided steel brake cables to replace the rubber ones .

It is possible debris entered the rotors since I changed them outside on a breezy day. I don't have the luxury of a garage

 

to properly set bearing preload, tighten the spindle nut 20 foot pounds while spinning the wheel. THEN BACK THE NUT OFF COMPLETELY. repeat dont leave the nut torqued!! that will ruin the bearings. spindle nuts get hand tightened only! hand tighten it and then go one or 2 notches more if you have to for the retainer cap cotter pin alignment as long as you dont have any play in the bearing. you are torqueing the spindle nut to seat the bearing properly, then you back it off and hand tighten it for the preload. you will destroy the bearings in a hurry if you leave the spindle nut torqued to 25ft lbs!

 

I set preload by feel as fordtrucksrule does. Once you've done enough of them you kinda get the feel. Out of curiosity, I checked my Chiltons and their procedure was to tighten to 20-25 ft/lbs and then back off 1/8 turn.

Make sure you're using high-temp grease for disc brakes. Disc brakes impart a fair amount of heat to the hub/bearing assembly which some greases can't tolerate. The grease will tend to liquify and run from the bearing.

I can't help but think your calipers might still be hanging up. You'll have to eliminate this possibilty before blaming everything on the bearings. The fact that the truck has that high of rolling resistance kinda steers me back to the calipers. High temps from calipers not retracting and improper grease can wreak havock on the bearings too.

Randy

 

I think the problem will be twofold. First, I didn't back off from the 25 ft-lbs for the nut. Second, while I used high temp bearing grease for the packing I was shooting water resistent (marine trailer) grease in the kingpin nipples. I heard that the grease from the kingpin area can move to the bearings through the gap between the break guard and the spindle.

I didn't think those areas were connected...oops. I use the marine grease in steering linkage because I like to go romping through puddles occasionally.