Rear Axle Seal failure

[chris.817]

Hi folks,

I know this is a worn out subject, but I'm fixing this issue now for the fourth time.

I'm the original owner with 225k miles. My driver's side seal failed the first time at about 175k miles. I replaced everything including the bearing. It failed again at about 200k miles. I figured I put the seal in poorly so just replaced the seal the second time.

A bit later, the vehicle was in an accident and was pulled out of a ditch by tow truck with driver side wheel. I didn't know this until the damage was fixed and I realized the wheel was visibly bent. Replaced wheel. Within months the seal was leaking again. I figured the bent wheel/tow truck messed up the bearing so I replaced the entire setup again. Bearing , seal, o-ring, ABS wheel etc.

Now, 12 months later it's leaking again. I decide the shaft must be bent so I ordered a shaft. Reading today I realize maybe it's the damn vent that's bad and I'm building up pressure (thank you t4r forum). I removed the vent and sure enough I got what sounded like air pressure release when it finally came off. I can, however, blow into it and it seems to work with a good amount of pressure against it?

So... how much pressure should it take to actuate the thing? It's 20 years old and could not be too expensive. Just replace it? Anyone think that's my culprit? I have to assume that my seal is bad regardless and replace it but sure would be an easier job to not replace the axle, bearing, etc.

And in all this time, passenger side still dry a a bone...

Thoughts?

Thanks
Chris

 

[Brian.]

Are you aware that the Seal you can buy from Toyota is physically different than what was installed and the new seal doesn't have great contact with the bearing spacer which has been causing lots of people to have to do the job over (and over, and Over) again...

Timmy has a great video on this:

https://www.youtube.com/watch?v=AVhSDnw2ugo

 

[jgue467]

... how much pressure should it take to actuate the thing? ...

What do you mean by actuate? Its just a breather, shouldn't build up any pressure, which is what maybe causing your repeated leaks? So perhaps it is partially clogged (tube) and building pressure. I think you should replace the tubing and a fresh breather to be sure. Just my thoughts given what you've been thru. You don't want to hear about mine....

Luck :cowboy:

 

[BoomerBob]

Sounds like you found the problem. A plugged vent. It should be able to allow air in or out freely. If you get into mud then an extension tube up higher should take care of the issue permanently.

 

[chris.817]

I thought the breather was one way so it would not allow water in but air out? There is currently no tube. Just a 1 inch cap that seems to pop up when blown into... That's not the way it works huh?

Guess that's an easy fix...

 

[Brian.]

I thought the breather was one way so it would not allow water in but air out? There is currently no tube. Just a 1 inch cap that seems to pop up when blown into... That's not the way it works huh?

Guess that's an easy fix...

That's exactly what's stock (for the rear axle) and how it works, just a 1-way valve that lets pressure out. Common "mod" to install a hose that relocates that valve up higher for foul-weather/conditions driving. Not really needed for a street rig, I did it mostly because I bought the wrong replacement (bought the type for the remote application, modified the original housing to accept my hose).

 

[brillo_76]

Those vents rust up big time in the rust belt. Should probably be checked every year after the vehicles are over 10 years old. They aren't very expensive. So maybe best to change with the radiator exchanges as that's a lot cheaper then changing the bearings and seals.

Sent from my SM-J337V using Tapatalk

 

[chris.817]

Thanks for the insight folks.

I watched that video last time I did this but don't remember comments on the seal. I'll watch again. And buy a new vent. And brake shoes. And do the seal again too...

 

[chris.817]

Watched Tim's video. Guess I'm replacing everything again. And flipping retainer. And maybe buying some new tools!!!!!

 

[BoomerBob]

Watched Tim's video. Guess I'm replacing everything again. And flipping retainer. And maybe buying some new tools!!!!!

Not sure what special tools you might need but I used a claw hammer with a fairly straight claw to easily remove the seals and a seal setting kit to send the new one home but I recently read about someone using an oil filter. In that vein lots of things could be used including a can of Campbell soup. I'm not a fan of these last two because I like to hear that solid sound when the seal is fulling seated. Not sure you can get that with a filter or can.

Another thing you can do while you have the axle out is to carefully remove the seal on the side of the bearing your can get at and so you can repack the bearing with grease since you have it out unless you plan on replacing the bearing anyway. There are videos on YT to show how to do this.

Edit: Nevermind. Looks like you'll be doing the full bearing replacement job. Just did it myself. Not bad at all with the tool Timmy recommends and a 20 ton press.

 

[Andy in Pa]

Those vent tubes don't even need a vent cap on top. If they are run somewhere protected by the elements (as in, no water can get in) they can be left open. I have bent a small piece of tube and clamped it at the top of breather tubes before too. They should be free-flowing no matter what.

 

[chris.817]

Update: I am doing the full replacement, again. I did buy the new vent. No different than than the original as far as amount of pressure it take to vent so that was not my problem.

After pulling out the axle, the inner spacer seems a bit chewed up like the machinist did not put them far enough onto the axle. Which also seems to rule out the idea of putting it on backwards per Timmy's instructions.

So as of right now, I do not have a smoking gun as to why this has failed again...

 

[mtbtim]

Update: I am doing the full replacement, again. I did buy the new vent. No different than than the original as far as amount of pressure it take to vent so that was not my problem.

After pulling out the axle, the inner spacer seems a bit chewed up like the machinist did not put them far enough onto the axle. Which also seems to rule out the idea of putting it on backwards per Timmy's instructions.

So as of right now, I do not have a smoking gun as to why this has failed again...

Well, on this round you're replacing the axle and that's good because maybe your axle shaft is slightly bent from the accident. There's also a chance the bearing case is bent too. The bearing case has ears that the serrated bolts are drawn into. On a hard enough impact, those ears could be bent so take a good look at it when you get it apart. What's interesting is [MENTION=169810]calnhob[/MENTION] (aka Wei) has had a similar issue with his driver side. I helped him with an axle seal job and was miffed why the axle wouldn't pull out easily. We suspected the bolts were bent but didn't have any available so we made it work having to give the axle some encouragement with a mallet going back in. He found later on his axle seal was leaking again so he gets himself a used axle. When we are taking off his brake backing plate so we can swap it over to the donor axle, we take a good look at the bearing case and realize one of the ears was visibly bent out of whack. We got it all back together for a second time with a different axle and bearing case from the donor assembly, confirming a good mating inner axle seal and inner retainer and think he's now good to go. But, he says it's now leaking once again and I told him the only other thing that could be causing this is a bad breather unless there's something in play we're not recognizing. With a new bearing, new seal, confirming a proper mating of the retainer and seal, confirming you have a working breather, and ruling out the possibility of a bent axle or bent bearing case, there's nothing else that could be causing the seal to be failing. I don't know if Wei figured it out but he's the only other guy I've heard of that has had a similar problem like yours.

The inner retainer being chewed up meant it indeed wasn't pressed on far enough to the axle and the bevel side was grinding into the inside of the axle housing. This is why the flip method is great because you can keep the retainer in pretty much the original position the retainer was from the factory. The seal redesign by Toyota has the seal lip now sitting 2mm more inboard. When you flip the retainer, you now don't first have to push past the 2mm bevel to get up onto the polished shoulder where you want to seal to ride.

As long as you are doing some type of grease or sharpie test to confirm you have a good mating of the inner axle seal and inner retainer and your breather is working, you should be good to go. For the grease or sharpie test, go ahead and snug up the axle to the axle housing with the 4 nuts, spin the axle a few times and then pull it back out. Ideally, you want the seal lip riding close to the center of 10mm polished shoulder of the retainer.

 

[Drcoffee]

A possible solution to leaking axle seals - Toyota 4Runner Forum - Largest 4Runner Forum

Check this thread out. I explain in detail whats needed to be done.

 

[BoomerBob]

Now, 12 months later it's leaking again. I decide the shaft must be bent so I ordered a shaft. Reading today I realize maybe it's the damn vent that's bad and I'm building up pressure (thank you t4r forum). I removed the vent and sure enough I got what sounded like air pressure release when it finally came off.

Update: I am doing the full replacement, again. I did buy the new vent. No different than than the original as far as amount of pressure it take to vent so that was not my problem.

These two statements conflict with each other. Only one can be true. It either did or didn't release pressure when you removed it. They can appear to be the same functionally but not in practice.

 

[JMat]

These two statements conflict with each other. Only one can be true. It either did or didn't release pressure when you removed it. They can appear to be the same functionally but not in practice.

Sometimes when I change the fluid in the rear diff I've had the same thing happen to me and couldn't figure out how there could be pressure to be released. In my case I believe it was a slight vacuum and not pressure at all. These diff's build up heat in the summer(expanding the air) and release that pressure. Since these valves are only one way, when the temps drop a lot in the winter and the air inside the diff condenses it makes sense to me that it could leave a slight vacuum. When you open the thing up it may be hard to tell the difference. I always open the fill hole first to before I drain the diff to make sure it's not stuck and that's when I've heard this.

 

[BoomerBob]

Sometimes when I change the fluid in the rear diff I've had the same thing happen to me and couldn't figure out how there could be pressure to be released. In my case I believe it was a slight vacuum and not pressure at all. These diff's build up heat in the summer(expanding the air) and release that pressure. Since these valves are only one way, when the temps drop a lot in the winter and the air inside the diff condenses it makes sense to me that it could leave a slight vacuum. When you open the thing up it may be hard to tell the difference. I always open the fill hole first to before I drain the diff to make sure it's not stuck and that's when I've heard this.

I can see how that could happen on a one way valve which tells me this shouldn't be a one way valve. I get why it is; to keep water and dust out but it sounds like a simple breather filter that allowed air both ways would be better. For those who see a lot of mud, sand, and water or any combination of; an extension tube with the breather mounted someplace where those things can't get to it makes sense.

I've read of people drilling a hole so the tube vents inside the cab where it's always clean dry(ish) air.