Rear axle seal failure question

[BlackRustBucket]

Hey all, I went to change my rear drums yesterday and opened it up to find it caked with gear oil grease. I've replaced this same seal about 7-10k ago. I know it's a common failure but would just a clogged diff breather alone cause it to blow out? How should I fix the breather if that's the problem (without doing the extension mod)

 

[Cuco]

Cuco-TheOriginal
I am using Tapatalk on my Iphone

 

[nobb]

Clogged breather can be one reason. Also check your drum brakes. If they are too tight, the drag causes the seals to get hot for prolonged periods which also leads to failure.

 

[mtbtim]

Hey all, I went to change my rear drums yesterday and opened it up to find it caked with gear oil grease. I've replaced this same seal about 7-10k ago. I know it's a common failure but would just a clogged diff breather alone cause it to blow out? How should I fix the breather if that's the problem (without doing the extension mod)

The breather is simple to pull off and inspect. It sits right on top of the 3rd member closer to the driver side. Just spin it off with a wrench, blow through it and see if it lets air escape. But, there's a very good chance this isn't the reason for your continued axle seal failure problem. It's for the reasons I state below.

You learned the hard way that this repair is not as simple as just replacing the seal. Here's why:

Toyota redesigned the axle seal some time in the past. The new seal design has the lip of the seal sitting more inboard than the original. Without changing the retainer position on the axle, the lip of the seal will be barely riding on the polished shoulder of the retainer. With a little bearing play from worn out axle bearings, the lip of the seal will sometimes ride on the non-polished bevel and the seal will wear out prematurely and fail.

If you're tired of contaminating your brakes and replacing seals, you need to fully service your axles by either doing the press work yourself or farming it out to a local machine shop that knows what they are doing. What I mean by fully servicing is you need to replace your bearings and reposition the retainer so it meets up better with the seal lip.

If you have an ABS rearend, you can reuse the ABS gear and both retainers if you pull off the parts rather than cut them off. For the retainers, swap the positions. Put the one that was against the bearing in the position where it meets up with the seal. Then, put the one that was originally meeting up with the seal against the bearing. The reason for swapping the positions is because the seal lip wears a mark into the retainer. This area where the seal lip has been riding for thousands of miles has actually worn down the metal every so slightly. If the new seal actually rides in this same area, the seal won't be as tight compared to the seal lip riding on a non-worn retainer.

If you have an Non-ABS rearend, you only have one retainer against the bearing and you should replace it.

Also, when the seal fails and lets gear oil surround the bearing, the gear oil gets into the bearing casing and washes out the grease. The bearings are lubricated with grease and not gear oil. This compromises the bearing because it's not being lubricated properly.

[MENTION=102606]infamousRNR[/MENTION] and I have a couple videos you could follow as a tutorial if you want to do the whole job yourself. At the very least, by watching the videos you'll see for yourself why your seals keep on failing.

<iframe width="560" height="315" src="https://www.youtube.com/embed/AVhSDnw2ugo" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/vW25hvODHcs" frameborder="0" allowfullscreen></iframe>

 

[BlackRustBucket]

Clogged breather can be one reason. Also check your drum brakes. If they are too tight, the drag causes the seals to get hot for prolonged periods which also leads to failure.

That's a good idea about the heat. I believe the last time when I replaced the seal and drum shoes, the adjuster wasn't working right on my first drive (on the side that's now leaking) and smoke was pouring out of my wheel when I pulled back into the driveway. I readjusted it and no issues since so I figured I was good but maybe I fried the brand new seal. Thanks for the input

 

[BlackRustBucket]

The breather is simple to pull off and inspect. It sits right on top of the 3rd member closer to the driver side. Just spin it off with a wrench, blow through it and see if it lets air escape. But, there's a very good chance this isn't the reason for your continued axle seal failure problem. It's for the reasons I state below.

You learned the hard way that this repair is not as simple as just replacing the seal. Here's why:

Toyota redesigned the axle seal some time in the past. The new seal design has the lip of the seal sitting more inboard than the original. Without changing the retainer position on the axle, the lip of the seal will be barely riding on the polished shoulder of the retainer. With a little bearing play from worn out axle bearings, the lip of the seal will sometimes ride on the non-polished bevel and the seal will wear out prematurely and fail.

If you're tired of contaminating your brakes and replacing seals, you need to fully service your axles by either doing the press work yourself or farming it out to a local machine shop that knows what they are doing. What I mean by fully servicing is you need to replace your bearings and reposition the retainer so it meets up better with the seal lip.

If you have an ABS rearend, you can reuse the ABS gear and both retainers if you pull off the parts rather than cut them off. For the retainers, swap the positions. Put the one that was against the bearing in the position where it meets up with the seal. Then, put the one that was originally meeting up with the seal against the bearing. The reason for swapping the positions is because the seal lip wears a mark into the retainer. This area where the seal lip has been riding for thousands of miles has actually worn down the metal every so slightly. If the new seal actually rides in this same area, the seal won't be as tight compared to the seal lip riding on a non-worn retainer.

If you have an Non-ABS rearend, you only have one retainer against the bearing and you should replace it.

Also, when the seal fails and lets gear oil surround the bearing, the gear oil gets into the bearing casing and washes out the grease. The bearings are lubricated with grease and not gear oil. This compromises the bearing because it's not being lubricated properly.

[MENTION=102606]infamousRNR[/MENTION] and I have a couple videos you could follow as a tutorial if you want to do the whole job yourself. At the very least, by watching the videos you'll see for yourself why your seals keep on failing.

<iframe width="560" height="315" src="https://www.youtube.com/embed/AVhSDnw2ugo" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/vW25hvODHcs" frameborder="0" allowfullscreen></iframe>

Excellent information, thanks for taking your time to share. When I bought the vehicle the same seal was bad and the previous owner never figured it out which ruined the rear diff pinion bearing after it lost all it's oil eventually. During that trouble shooting I did both wheel bearings before trying the center chunk, so the bearings and parts are at least new (no rear abs btw). When I get the axle out this time for the seal I'll take a look and see if where it's riding has left a mark (especially since it probably was dry for a while riding on the surface). If there is could I just have the bearing slid one way or the other slightly or am I missing the idea?

 

[JohnMc]

My RR seal was leaking and *all* I did to fix it was un-stick the breather. The seal itself was fine.

When the diff warms up (which is normal) the air expands, and that air has to go somewhere. If it can't go out the breather, it does out one of the seals. They're not designed to hold pressure.

Check that breather, if it's clogged, unclog and unstick it and clean up the drum and shoes, see if the problem reoccurs.

 

[mtbtim]

Excellent information, thanks for taking your time to share. When I bought the vehicle the same seal was bad and the previous owner never figured it out which ruined the rear diff pinion bearing after it lost all it's oil eventually. During that trouble shooting I did both wheel bearings before trying the center chunk, so the bearings and parts are at least new (no rear abs btw). When I get the axle out this time for the seal I'll take a look and see if where it's riding has left a mark (especially since it probably was dry for a while riding on the surface). If there is could I just have the bearing slid one way or the other slightly or am I missing the idea?

When Sean and I helped [MENTION=148218]JZiggy[/MENTION] with his Non-ABS rearend, we pretty much determined we had to flip the retainer orientation. We had the retainer bevel facing the bearing rather than facing the seal. This allows the seal lip to ride more towards the center of the polished surface of the retainer rather than really close to the edge of the non-polished bevel. Another forum member, [MENTION=78997]Drcoffee[/MENTION] came up with the retainer flip technique and has an extensive thread on the subject. Watch our Non-ABS video. We show without a doubt that flipping the retainer is the way to go. Good luck with the repair.

 

[JohnMc]

If there is could I just have the bearing slid one way or the other slightly or am I missing the idea?

You can't, or more correctly shouldn't, have the bearing moved, but you can move the ring that the seal touches. It's pressed into place, it can be moved.

The bearing gets pressed fully onto the axle shaft, then you have the ABS tone ring and the sealing surface ring. It would be 'nice' if Toyota made spacers for all these things, or made them wider so they could all be pressed together, because that's what pretty much any machine shop is going to want to do. But there needs to be a gap, otherwise that sealing surface sits neatly outboard of the seal itself.

 

[mtbtim]

You can't, or more correctly shouldn't, have the bearing moved, but you can move the ring that the seal touches. It's pressed into place, it can be moved.

The bearing gets pressed fully onto the axle shaft, then you have the ABS tone ring and the sealing surface ring. It would be 'nice' if Toyota made spacers for all these things, or made them wider so they could all be pressed together, because that's what pretty much any machine shop is going to want to do. But there needs to be a gap, otherwise that sealing surface sits neatly outboard of the seal itself.

John, you're absolutely correct regarding an ABS rearend but the OP has a Non-ABS rearend.

OP, in order for you to get the c-clip installed above the retainer, the bearing needs to be fully seated into the housing and the retainer needs to be flush against the bearing. So, there's no adjustment possible. The only way to improve the seal/retainer mating is to flip the retainer orientation.

 

[catrains]

Hey all, I went to change my rear drums yesterday and opened it up to find it caked with gear oil grease. I've replaced this same seal about 7-10k ago. I know it's a common failure but would just a clogged diff breather alone cause it to blow out? How should I fix the breather if that's the problem (without doing the extension mod)

I have been thru this before . axle damage at the seal lip area usually does it... one time it was the axle was bent slightly. a vehicle hit my driver side rear wheel . this caused that leak , created a problem for the seal to ride properly over this area.

remove breather and see / test if it is plugged ..if not the the axle is the problem. new bearings also .

 

[Scramble]

Hey all, I went to change my rear drums yesterday and opened it up to find it caked with gear oil grease. I've replaced this same seal about 7-10k ago. I know it's a common failure but would just a clogged diff breather alone cause it to blow out? How should I fix the breather if that's the problem (without doing the extension mod)

My clogged breather caused my RR seal to leak. I did the extended breather & the leak stopped. It took me 15 min to do the mod. Easiest mod ever. I ordered everything from Amazon, cost maybe $35.

 

[nobb]

When Sean and I helped [MENTION=148218]JZiggy[/MENTION] with his Non-ABS rearend, we pretty much determined we had to flip the retainer orientation. We had the retainer bevel facing the bearing rather than facing the seal.

With all due respect towards you and Dr Coffee's work on this issue, flipping the retainer caries certain risks such as over stressing/tearing/damaging the seal or popping out the garter spring during install. That's the whole purpose of the bevelled edge in these mechanical sealing applications. I know that in 99% of cases it's probably fine but just putting this out there.

When I took measurements with the new seal design, mounting the retainer 2-3mm inboard is sufficient to ensure a good seal, maintain clearance with the axle housing, and still minimize install risks.

 

[mtbtim]

With all due respect towards you and Dr Coffee's work on this issue, flipping the retainer caries certain risks such as over stressing/tearing/damaging the seal or popping out the garter spring during install. That's the whole purpose of the bevelled edge in these mechanical sealing applications. I know that in 99% of cases it's probably fine but just putting this out there.

When I took measurements with the new seal design, mounting the retainer 2-3mm inboard is sufficient to ensure a good seal, maintain clearance with the axle housing, and still minimize install risks.

You are correct that the beveled edge is to facilitate insertion into the seal. But, after holding the seal and retainer in my hand and seeing how easy the retainer slides into the seal, I think you'd almost have to try to damage it because the seal is very pliable. The increased pliability is probably something the Toyota engineers did to improve the seal design to make the seal last longer as bearing play adds increased stress on the seal.

Your mounting of the retainer in a different position more inboard will work for the ABS rearends but you are coming close to rubbing the axle housing. With the flipped orientation, you don't have to worry about hitting the axle housing at all.

Now, with a "Non-ABS" rearend, which is what the OP has, there is only one retainer which sits flush against the bearing. You can't reposition it more inboard because you then can't get the c-clip in position. The retainer has to sit flush against the bearing so you're only option to get a better mating with the redesigned seal is to flip the orientation.

I hope this makes sense. If anyone reading this still doesn't follow what I'm talking about, please watch the Non-ABS video I posted above, and you'll see how [MENTION=102606]infamousRNR[/MENTION], [MENTION=148218]JZiggy[/MENTION] and I prove without a doubt the flipped retainer technique is the way to go when performing a rear axle seal/bearing job on a Non-ABS rearend.

 

[JZiggy]

If I recall correctly, even the non-beveled side of the retainer still has a small chamfer. It's not like it's sharp. If you're careful and the seal is greased (as it should be) I don't think there is a high concern to screw up the seal while inserting the axle shaft.

But that is a good point -- when flipping the retainer one should take extra caution to protect the axle seal while fitting the axle back in.

Personally, I would gladly trade good sealing for having to install the axle more carefully

 

[thegipper]

My clogged breather caused my RR seal to leak. I did the extended breather & the leak stopped. It took me 15 min to do the mod. Easiest mod ever. I ordered everything from Amazon, cost maybe $35.

Scramble's experience is identical to mine. Found a tiny bit of oil on the abs gear and checked the breather. Breather was totally clogged so I did the extended breather mod, abs ring has been bone dry ever since.

Obviously it isn't the only cause but it is certainly one of them...

 

[BlackRustBucket]

Ok so...even though I feel like I did the seal yesterday it was 3 years ago and I've completely forgot that I do actually have the ABS ring. I started pulling up some exploded diagrams and started to think the abs one looked awfully familiar so I went out and checked for an abs sensor and I have one. I watched the video, which is very good, and it all has come back to me enough that I could follow the discussion now lol. My plan as of now, is to check the breather and unclog it if needed...and then do just the seal since the bearing is new and shouldn't have too much play (although it may fail prematurely down the road from the gear oil displacing the grease in it but i'm gonna throw the dice). I have a spare seal already from last time anyway and I still think there's a chance I could of distorted the leaking one when the brake was dragging and smoking on my test drive originally. If it still doesn't do the trick I'll be getting a new bearing and associated parts, and have the outer ring flipped. I'll take a few pics and update my findings for anyone interested. I really appreciate the direction and the video reference though, it def helped me save a lot of time. Thanks

 

[mtbtim]

Ok so...even though I feel like I did the seal yesterday it was 3 years ago and I've completely forgot that I do actually have the ABS ring. I started pulling up some exploded diagrams and started to think the abs one looked awfully familiar so I went out and checked for an abs sensor and I have one. I watched the video, which is very good, and it all has come back to me enough that I could follow the discussion now lol. My plan as of now, is to check the breather and unclog it if needed...and then do just the seal since the bearing is new and shouldn't have too much play (although it may fail prematurely down the road from the gear oil displacing the grease in it but i'm gonna throw the dice). I have a spare seal already from last time anyway and I still think there's a chance I could of distorted the leaking one when the brake was dragging and smoking on my test drive originally. If it still doesn't do the trick I'll be getting a new bearing and associated parts, and have the outer ring flipped. I'll take a few pics and update my findings for anyone interested. I really appreciate the direction and the video reference though, it def helped me save a lot of time. Thanks

Before you bolt the axle back to the housing, please do the grease test to see where the lip of the seal is riding on the retainer. If it's barely riding on the polished shoulder next to the bevel, you're probably going to have another failure. If you have a machine shop near you, maybe they could pull it off flip it for you and then press it on where you want them too. If they don't have the right tools to pull it off, they'll probably cut it off but you're only out the cost of a retainer which isn't that much. I've come to the conclusion with the retainer flipped around, 5mm of polished axle showing should put the seal lip very close to perfectly dead center of the polished surface. The polished part of the retainer is 10mm wide.

Good luck and let us know how it goes. Better yet, if you do go the route of flipping the retainer, take a couple pictures. A picture of your first grease test showing where the seal is currently riding on the retainer and then a picture showing another grease test after you flipped the retainer.

 

[albeck8862]

Sorry if I'm repeating what was said earlier in the thread, but by all means check the axle breather if you've done the seal work & still have issues. I had replaced seals, bearings,races & abs rings twice before realizing the vent was clogged , once I changed that it was night & day, end of problem

Sent from my MotoG3 using Tapatalk

 

[St Runner]

I would recommend three things. Do the grease test. Use an OEM seal not an aftermarket. Check around the outside edge of where the seal sits. If the seal was removed incorrectly it will gouge the metal and the oil will go around the outside of the seal even if it is seated correctly. This can be corrected with a good sealant.