As noted below, more than just going to 21, there is a procedure before that:
Then proceed to assembling the wheel bearings:
* Drive in the new race(s) in the same manner as removing the old race.
* Pack new inner bearing, put in inner bearing
* Drive in new seal
* Pack outer bearing
* Either put outer bearing into it's race and slip whole unit onto spindle or slip unit on spindle then put outer bearing in. Be careful not to dump new/clean outer bearing on ground when putting it on spindle.
* Put washer with tab on it for the slot in spindle on.
* Put inner spindle nut on.
Now there are two schools of thought on properly tightening the wheel bearings. First is the method documented in the Toyota Factory Service Manual:
* Tighten the nuts finger tight, then using a spring scale, measure and record the seal drag while turning the hub with the scale attached to a wheel stud
* Then tighten the nut and re-measure the bearing drag until it reads about 3-8 lbs more than the seal drag alone.
The second method seems to produce similar results and is a bit more straight forward:
* Torque spindle nut to 43 ft. lbs.
o Spin hub right 4-5 rotations
o Spin hub left 4-5 rotations
* Loosen inner spindle nut
o Spin hub right 4-5 rotations
o Spin hub left 4-5 rotations
* Torque spindle nut to 43 ft. lbs.
o Spin hub right 4-5 rotations
o Spin hub left 4-5 rotations
* Loosen inner spindle nut
o Spin hub right 4-5 rotations
o Spin hub left 4-5 rotations
* Torque spindle nut to ~21 ft. lbs.
The idea behind the second method is to ensure the bearing is fully seated in the grease and then the final torquing sets the pre-load fairly accurately. I used the second technique on my first rebuild (I didn't have a spring scale then) and I found the bearings a bit tight. In fact they seemed to be getting a bit hot on a highway trip to go wheeling. However, after two days crawling rocks, they seemed to settle right in. When I got back, I picked up a scale and measured the bearing drag and both sides were about 8 lbs. total (don't know what the oil seal drag was and I wasn't about to find out :-), so I guess it worked OK.