Pinion Seal Question

[superdart]

Ever since I rebuilt my 8.25 axle the pinion seal has leaked. At first I thought I just over filled it, but it just keeps seeping until it's low.

Most likely I managed to damage the new seal during assembly, so I'm going to toss a new seal on it.

My question: I stopped by O'Reilly and picked up a National (Moog) pinion seal. When I pulled it out of the box, there is no red or green painted surface on the seal ring where it contacts the case. This is the first time I've ever seen a seal without that paint.

Is that normal?

Will it still seal against the axle housing, or did I just get a defective seal?

 

[superdart]

......Crickets......

:dontknow:

 

[fishy68]

I've never saw one that wasn't painted either but I don't rely on the paint to seal it anyway. I use a thin layer of shelac on it.

Now onto your leak:

Have you verified where the leak is actually coming from? If you haven't verified where the oil is actually coming out of do so before you disassemble it. It can not only leak from between the seal and yoke but it can also leak from between the seal and housing and can even leak out between the pinion to yoke splines. If it's leaking from the splines use a little rtv on the splines when you assemble it. If it looks like it's coming out between the yoke and seal inspect the yoke very carefully when you remove it to make sure there isn't any sign of a groove worn where the seal rides. Sometimes it doesn't take much of a groove to cause a leak. If there is you need to either replace the yoke or install a speedy-sleeve. If it looks like its coming otu between the seal and housing seal that area with shellac when assembling like I mentioned above.

Verify'ing it before you tear it apart may save you from doing it all over again.

One last thing, doesn't the 8-1/4" use a crush sleeve to set pinion bearing preload? If so removing the yoke can disturb the setting and cause mechanical issues. I always replace the crush sleeve with a solid spacer and shims so if I have to take it apart again it doesn't disturb the setting.

 

[superdart]

IDing the leak before disassembly will be hard, since I have a dust cone attached to the yoke that covers the seal area. All I can say for sure is that the fluid is leaking from under that cone, so it's either the case-to-seal or seal-to-yoke. I would think if it were the splines that were leaking it would be running down from the from of the yoke by the nut.

I guess I can take it apart, re-check the yoke shaft surface, replace the seal, use shellac AND RTV the splines.

The 8.25 does use a crush sleeve, but I just put that in when I rebuilt it. I'll put in another if necessary, not really a big deal.

For my first ever axle rebuild, I'm pretty happy if a pinion leak is the worst thing I need to remedy. Otherwise the axle is hanging tough and not making any noise after the first few hundred miles.