Axle Seal Leak: Fixed?

[lockedlex]

So about 4000 miles ago I changed my rear axle seals (wheel bearings are fine) because I found out that it was leaking after 190k miles (also replaced rear brake shoes).

Reently, I pulled the ABS sensor and noticed that it was heavily coated with diff fluid. Pulled the Driver axle and there was fluid pooled in the axle housing. Passenger side not so much, but still ABS sensor had gotten heavily coated.

So replaced the seals again, but this time didn't punch it all the way in, so that it wouldn't rest so close to the beveled edge. Used the grease test to confirm that the seal went from the edge of the bevel to about 2mm closer to center. Put it all back together (should have read about the redesigned seal drama before I did the job).

Drove about 600 miles. Pulled the Driver ABS sensor and had a slight coat (barely enough to show on paper towel). Keep in mind that the Driver side Axle Housing was the one that was pooling with fluid initially. Passenger side ABS sensor was pretty much dry, just the slightest coat/sheen of fluid.

Added another 700 miles and driver ABS again had barely any coating, pass was pretty much dry. I heard that a bearing can also keep some fluid so it's possible that it's dripping back into the axle housing area a little and that's what I'm seeing.

For the past 1300 miles (600+700), no additional fluid on the brake shoes and using a boroscope shows no fluid pooling in the axle housing at all (bottom of Axle Housing is pretty much dry).

It is safe to say that a leak at this point would be more obvious (like the first and second time I had to replace it) by now? Could I be in the clear? I was planning to inspect it every 1k miles.

 

[mtbtim]

So, at 190k you're saying your rear axle bearings were fine? #1, rear axle seals usually fail for two common reasons, worn out bearings allowing for more than normal axle movement and #2, a clogged differential breather.

Another thing, the health of the bearing on the affected side is dependent on how long it was surrounded by gear oil. The gear oil can get into the bearing case and wash out the grease. The bearings need grease for lubrication, not gear oil. Now that bearing is compromised and might fail on you and maybe at a really inconvenient time like on a road trip far from home.

I think most people would recommend just doing the whole job and replacing the bearings because that's the best insurance you're not going to be forced to pull your axles again and repeat a bunch of labor after you have another axle seal failure.

If you end up deciding at a later date to replace the bearings, this video will help you out.

<iframe width="560" height="315" src="https://www.youtube.com/embed/AVhSDnw2ugo" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>

 

[thegipper]

I'll never understand why Toyota didn't just make the axle seal the size of the polished area of the axle. Why screw around with a retainer for the seal to ride on.

I hate to use the "jeep analogy" but my 95ZJ had a axle seal leaking. It was simple, remove the axle, replace the seal....done.

NO need to screw around with retainers, flipping retainers, grease tests and so on.

That jeep had 305k miles on it before that axle seal started leaking. Replaced the seal and it never leaked another drop.

 

[JohnMc]

I'll never understand why Toyota didn't just make the axle seal the size of the polished area of the axle. Why screw around with a retainer for the seal to ride on.

I hate to use the "jeep analogy" but my 95ZJ had a axle seal leaking. It was simple, remove the axle, replace the seal....done.

NO need to screw around with retainers, flipping retainers, grease tests and so on.

That jeep had 305k miles on it before that axle seal started leaking. Replaced the seal and it never leaked another drop.

I guess partly because where the seal rides is a wear surface. After 200K miles there's usually a noticeably worn groove. At that point, it's easier to replace the seal ring or even just move it than it is to replace the whole axle.

 

[thegipper]

That's what someone suggested before. Not sure why it was never a problem on my Jeep though?

 

[lockedlex]

I think the main issue is that Toyota moved the seal surface 2mm from it's original location on the new seals, why???

If they kept it where it was originally, we'd all be fine on these replacements. The Axle itself doesn't wear down (it's metal rubbing against a rubber seal), so it's not like there'd be a need to move the seal position.

Anyway, after the grease test on my last redo, I can confirm that the seal sits at least 2mm from the bevel edge (vs. pretty much right on the edge) after I didn't punch it in all the way.

My main question was more about when is an axle seal leak truly an axle seal leak?

I'm going to assume that based on most of the posts I've read, when it leaks again, it LEAKS noticeably and immediately to the point that brake shoes or the outside drums get wet again and certainly the axle housing will fill with fluid. After 1300 miles the axle housing dry.