Once you do one you'll have the fundamental knowledge to do any. The internet is an invaluable resource for information and can help you with things that may be different from axle to axle.
This write-up will be about the GM 14-bolt full-floater rear axle, found under 3/4 ton and 1 ton trucks and vans.
First thing is disassembly. Any one of us can take something apart, but like an engine there are some things you have to take note of first. Mainly, the carrier bearing caps and their position/sides of their pre-disassembly location. Also take note of the pinion housing assemebly. It's bolt pattern is 6 non-symmetrical bolt holes and it can only go on one way. Otherwise, just standard sorting of bolts for where they go.
Some specialty tools you will need to complete this job:
4" bearing seperator.
Hydraulic press (can be bought cheap at harbor freight, or home made if you're creative).
Air impact capable of 450 ft/lbs of torque. I got mine at NAPA for $125.
Large pipe wrench.
Dial indicator micrometer with a clamp-on mount.
Caliper micrometer (can also be found at Harbor Freight cheap, and digital).
Rubber mallet, 2 lb hammer.
Several various blocks and pieces of heavy steel.
A variety of large sockets, including 1 1/2".
Punches, drifts, etc.
Taps and dies would be nice, for chasing threads.
After you have it took apart, you need to press the old bearings off the carrier.
Here's the borrowed home made press I used:
And here's my bearing seperator:
It is IMPORTANT to wear your SAFETY GLASSES when operating a hydraulic press! I would also not recommend smiling, since flying metal is tougher than teeth. I also cover the family jewels when possible! I had to split my carrier by removing the ring gear to fit it in my press. Using various chunks of steel, washers and a socket I pressed the carrier bearings off, as well as the old bearings off the old pinion. Unfortunately I didnt get pics, as I do not posess 3 arms. Then I pressed the new bearing on the new pinion and carrier, and used a 1" round drift bar to knock the bearing races out of the pinion housing and installed the new ones.
Next was one of the hardest, suckiest parts of the process: installing the pinion into the housing and setting pinion bearing preload! I installed the pinion into the housing, dropped in the crush collar, dropped the smaller pinion bearing into the top and used the press and the old bearing to press it up on the pinion. Then I started the pinion yoke on, used the old washer and nut, and using my impact on the highest setting I began running down the pinion yoke against the crush collar. It is a long process of short blasts, with the socket only turning about 1/16" at times, until there is only about 1/16" or less play up and down:
Next I ran the old pinion nut off and installed the seal. Grease the rubber seal surface:
...and then put some black silicone on the outer rim of the seal:
...then used the rubber mallet to get it started:
Smacked it the rest of the way down with the 2#:
...then rolled the edge down with the rubber mallet:
Might as well take the time to clean up the pinion yoke where the seal rides with the wire wheel...
Grease it up...
and smack it in place:
Next shoot some WD-40 on the washer and put some high-strength thread locker on the pinion threads:
Then you finish off the pinion bearing preload. You want about 25-35 inch-pounds of rotational torque. WD-40 the bearings when you're trying to get the preload right. You could try setting your ft/lb torque wrench to 2 pounds but I doubt you'll get the right amount of torque since they arent designed to go that low. Best way I can describe it is tighten it until it feels right. It will be just a little hard to turn but you should be able to spin it with 2 fingers and when you let go it stops. Used bearings require much less preload, more like a front wheel bearing has.