If the bearing is bad, it will have small metal flakes on it, or extreme discoloration. If you change the bearing, you have to change the race too. If the outer bearing is bad, then I'd be a little suspect of the inner bearing too. That opens up a whole different can of worms.

 

I was under the impression that you could not remove the outer bearing by going into the axle from behind the pinion seal. I thought you had to go in from the front. If i'm wrong how do you remove the bearing?

 

I think you are over thinking this. I would put the new seal in and reassemble it just like it came apart. Once you torque the nut to spec, check to see if there is any play in or out on the yoke. If no play , I would try it like it is. Usually the seal gives out from age.
You have to remember that most front 4x4 axles have been used for very few miles when compared to the rear axle unless it was a full time 4x4.
Deep water and big tires off road are more likely to cause damage than a bearing going bad.

 

Lets slow down and re-group here.
There are two bearings on the pinion and both have the same wear on them. One is pressed on and one is not. The one that is not pressed on is located behind the yoke but is lubricated by the same oil as any other bearing within the differential.
Point is this:
If one bearing has gone bad due to heat or contamination then every bearing in the entire differential has been compromised and all will have to be changed.

If you have just a leak from the pinion seal, make sure that the seal is not damaged, or that the pinion does not have a goove on the sealing surface. If there is a groove, you will never seal this without repair. If the seal was damaged, or it is just not pliable any longer, then simple replacement will be more than sufficient.

Here is the pinion and the pressed bearing:



This bearing can only be replaced by removing the entire pinion. This means that the carrier has to be removed, and that means that the axle shafts have to also be removed.

That being said, I agree that this situation has a much easier solution and that solution has little to do with the beaings and more to do with the seal itself.
You do not want to mess with the bearing pre-load shims, or do you want to take this thing apart and get the pinion depth shims messed up or you will have to much tension on the bearings, and they will fail, or,,,,you will change the pattern on the gear mesh, and again you will find a failure.
Do make sure that you have the correct bearing pre-load, and dont get thins confused with the torque value of the pinion nut.If you put a pre-load value anywhere close to the 200 lb/ft that the pinion nut takes, the pinion will never rotate, and you will kill the bearings.
Pre-load the bearings with the correct amount of shims to obtain a nice rotation of the pinion with no end play. This is where the small torque wrench comes in handy. This is a small value, so dont get carried away.


How far have you taken this thing apart? Have you gone too far?

 

The big washer should be an oil slinger to keep the majority of the oil off the pinion seal. Did the pinion have any up and down movement before you pulled it apart? If so you can wiggle the outer bearing off and remove some of the shims behind it to tighten up the bearing. I have had to do this a couple of times in my trucks 30 year history. If there was some up and down movement, that could be what is making the seal leak. Ditto on putting some sealer on the splines when you put the yoke back on. If the bearing is pitted real bad or burnt, probably needs replacing. I have just put the bearing in before and not changed the race(Diff needs to come apart to replace the race.) If this is front axle, remember it only gets used ocassionally (compared to the rear end.) Later Bruce

 

I have removed all the parts in front of the outer pinion bearing. I am currently looking at the bearing itself which looks fine. It has no discoloration or rust and it spins fine when i turn the pinion. There is slight play up and down with the pinion. I have done nothing with the bearings or anything inside the axle housing. Can i just put it back together in reverse order with the new seal, nut and washer? I'm sorry but i'm just really confused on what pre-load is or how to do it or even if i have to do it.

 

Ther will be play with the yoke off. If you didnt check before dissambly, and want to check. Put everything back together without the seal. Tighten yoke up pretty tigh, no need to torque. Recheck movement, if fine pull yoke back off and install seal, put back together. If loose up and down Play( not in and out) pull bearing and pull some of the shims and recheck. The bearing preload they are talking about is rotational force to turn the bearing. You can't check this without pulling the ring gear. You will not be changing any of the gear lash settings( have to pull ring gear to do that. Bruce

 

Be sure to use the old nut ( presuming you have a new one) to reinistall the yoke to check. That way you won't ruin the self-locking part of the new nut.

 

Got it all back together and just wanted to say thanks to all! I bought a new yoke from Bronco Graveyard and installed that as well. Torqued the pinion nut to 215 lbs....what a job that was. So far no leaks and it seems to be working great!! Thanks again!