Last week I replaced my rear wheel bearing seal from advanced auto parts. I used the national brand that they have. Well a week later the seal failed.

I was hoping someone can help me with the timken seal part number.

I know there is an outer seal. By chance is there a inner seal as well.

 

There is not an inner seal. If your seal failed that quickly, either it improperly installed, the bearing is bad, or the seal surface on the axle is damaged. Be sure to check when you install the new one. BTW, National seals are better than Timken, IMO.

 

What do u mean by if the seal surface is bad how would I check that.

Also another question would over filling the rear diff make it leak.

When I replaced the seal I also replaced the bearings since I had it torn apart

 

If there are grooves or other damage on the axle shaft surface where the seal rides, they can ruin the seal very quickly.

Overfilling could make it leak, but it would have to be significantly overfilled. Make sure your axle vent isn't plugged, too.

 

When I tear it apart here shortly I will take a picture of the axle.

It said 2-1/2 quarts of 80w90 oil. I put close to 3 quarts not paying attention. Well I will go buy another seal and do it all over again.

 

Run your fingernail over the surface, too, to feel for grooves. Very minor ones should be ok, but not if they're deep.

Before you put the brakes back on, check for radial play in the bearing by trying to move the axle shaft up and down. It should be barely detectable, if at all.

 

 

Yeah, that'll do it. I think new shafts are pretty cheap at Rock Auto. I would probably go that route.

 

Since it's already apart I recommend inspecting/replacing the bearing and seal on the other side as well. The missing metal from that bearing is in the case. A thorough cleaning and sticking a magnet to the cover with RTV will make your repair more reliable.

 

Make sure your new shaft is the same as the old. 2wd is different than 4wd, and disc rears are different from drum rears.

I just had to replace an axle shaft recently, ordered one from rock auto. It was pretty cheap. Think it was only like $50.
That's my old one compared to the new one. Kept having seal leaks as well